| Game | Hardware | Problem(s) | Fix |
| 1942 | Capcom Z80 | Plane constantly firing | Common fault on these boards (and others of the same family) - one of the LS367s that handle control inputs was fried (position A4). |
| 1943 (1) | Capcom Z80 | Glitchy sprites in certain screen areas | Appears to be due to the +5V pins all being burned to a crisp, turn up 5V line and problem goes away - pins replated (self adhesive copper tracking with a liberal covering of solder) and the problem has gone away. |
| 1943 (2) | Capcom Z80 | Black screen | Wasted a lot of hours on this diagnosing the problem from different directions. Since the CPU showed life, and didn't seem to be resetting, I assumed the CPU RAM was fine. After chasing the problem from multiple directions, it kept coming back to things that were CPU controlled. This board has a lot of dull oxidisation, my piggyback RAM test had achieved nothing. Cleaned the pins and the CPU RAM and tried again, game came back to life. Replaced to fix. |
| Aero Fighters Ltd Edition | PSX based Namco | Controls messed up. Left = left+fire, etc. | These are sony PSX hardware gameboards. I put it into self test and noticed that the inputs actually checked out, so it had to be the game code itself breaking. On the main pcb is a set of 4 dip switches. ONE of them is a backup memory clearer. Switch them all on, turn game on, work out which is the PSX hardware test, turn that off, turn it on, off, turn all dips back off, and set the game back up in the test menu - problem resolved. |
| Air Duel (1) | Irem M72 | Sprites blocks of colour, sound duff | The sound issue was actually due to a known faulty mainboard, as I'd donated the working mainboard from this to a Dragon Breed. The top romboard seemed to have a problem anyway though, and was reading sprites as blocks of colour. I also had a totally knackered Ninja Spirit with a failed security chip and romset. Ninja Spirit mainboard also seemed dead but was actually just too much dirt on the edge connector. Cleaned up and swapped the roms from Air Duel onto it. Board fixed. |
| Air Duel (1) | Irem M72 | Sound cut out during play, game RAM NG 5 after this | Ram 5 on bootup is the pair of 256k SRAMs near the sound Z80, by the ribbon cables. I replaced these, and the problem remained. It appears that if the ram test fails, then the board won't even try to play sound, the SND interrupt will never start (samples still happen, these are produced by the security chip!). I made various attempts at diagnosing this, but it's a complex beast. Since I knew something between the Z80 and the YM2151 was at fault, I simply replaced every chip that linked them together. This worked :-) |
| Air Duel (2) | Irem M72 | RAM NG 7 | On the C board there are some LS245s around M4, one of these had been poorly replaced by a previous owner. RAM 7 is obviously the two large chips next to them, useful to know.. |
| Air Duel (2) | Irem M72 | Intermittent RAM NG 3 4 7 8 | This seems to all be C board RAM, game was returned to me as having this fault which I'd never seen when testing it previously. Suspect the poorly reflowed large interconnect was the problem, removed solder, resoldered and cleaned it up. |
| Air Duel (3) | Irem M72 | ROM NG 1 2 3 4 | Found dead address line on code ROMs on the C board, traced to poor contact on one of the layout jumpers. This seems to be a recurring problem. Removed horrendous reflow mess from the interconnects and resoldered them. |
| Air Duel (4) | Irem M84 | Crunchy sound on louder notes, getting worse with increased volume, with screen interference | Main power filter cap completely dead - 470uf/25v |
| Air Gallet | Cave | Boot failure, graphical glitches, sound glitches | The main work RAM had already been replaced, but one of the chips was actually faulty and causing the game to sit in a reset loop. Graphical glitches were caused by a ROM socket with cracked solder on the through holes due to rough storage and handling. Sound glitches were affecting one of the OKI chips which uses sample bank one. Found one pin on this ROM which seemed to be floating, again traced to solder problems on the ROM socket. |
| Alex Kidd The Lost Stars | Sega System 16 | Dead, CPU block missing | I had to install a standard 68k and decrypted ROMs on this to get it booting, and reverse a lot of low quality repair work to tidy the board up. Game is being returned shortly as samples are missing (I didn't know it was supposed to have any). |
| AR-3 | Atari System 1 | Rumbling from left speaker | This was making a rumbling noise from the left speaker, as if there was a really bad connection somewhere, but the actual sound being played was fine. The noise would continue and fade after the cab was switched off. Replaced TDA 2030 amp chip for left channel, no change. Then I noticed a 224 25V ceramic cap was physically damaged on that channel, replaced to fix. These glass encased ceramics are nearly impossible to source, but a standard ceramic disc capacitor of the correct rating will work fine. |
| Arabian (Atari version) | Player would continually jump | Tracing from pin 7 underside through a resistor pack, I noticed on one section of track, it appeared to be shorted to ground. Further investigation revealed IC13 (74LS368) had internally shorted the up input and ground. Replaced, now working. | |
| Argus | No sound | Someone had worked on the sound section before and replaced many caps with incorrect types, poorly fitted - end result amplifier immediately getting very hot. Reworked all of the previous work and sound now good. | |
| Armed Formation (1) | Rumbling / failing sound | 12v sound cap (470uf/16v) appears to fail on these types of Nichibutsu boards regularly, this one completely died - interesting note the Fujitsu datasheet for the amp recommends a 2200uf cap for this circuit. | |
| Armed Formation (1) | Corrupt text layer, black bar above certain characters only | ROM tested good, RAM passed piggyback test, while piggybacking attached devices discovered the 74LS273 in 9B was bad. Replaced to fix. | |
| Asterix | Coin 1 stuck on | Suspected one of the input pulldown arrays at first, replaced relevant Konami part but problem remained. Traced to 74LS257 in 16C which was stuck, replaced to fix. | |
| Athena | SNK Ikari Warriors | Small amounts of sprite corruption when certain sprites drawn | Located sprite ROMs, did the quick and easy 'remove them one by one until the problem goes away' test, and noticed P9 was the culprit (or victim!). However, P9 verified as ok in the ROM reader, and when placed into the P8 socket, the problem was absent. I was about to start scoping the signals on the P9 socket when I noticed that each ROM has an associated pullup resistor array. The one for P9 was fitted at an angle, and at one end the pin wasn't even touching the PCB. Manufacturing defect, removed the array and refitted it properly, problem fixed. |
| Aurail | Sega System 16 | Jailbars on the backgrounds, flashing colours, messed up title screen | The 1mbit 28 pin mask roms can be read as 27C1000s if you build a tiny adapter. take a 32 pin socket, bend pin 30 outwards, and run a wire from pin 32 to that leg. Plug rom into this and any eprom reader should cope with it. Two roms in the tile section verified as bad, replaced with two 27C1000s, fixed. |
| Bad Dudes VS Dragon Ninja (1) | Data East MC68000 | Distorted music | Someone had previously replaced the op-amp. I replaced it with another one, but the fault remained. Next I changed all the electrolytic caps surrounding the op amp, but the problem still remained. Then I replaced the music channel DAC, which proved futile. In a fit of annoyance I shotgunned the rest of the sound section, and the fault came down to a tiny tantalum cap right next to the op-amp... You live and learn. |
| Bad Dudes VS Dragon Ninja (2) | Data East MC68000 | Crackly music | Similar to the above but this time it came down to the DAC at 4M. You can check this on a scope, the music waveform at the DAC should look clean when not connected to the rest of the circuit, this showed a noisy waveform with a ceiling and crackles above the ceiling occasionally. |
| Bad Dudes VS Dragon Ninja (3) | Data East MC68000 | Some graphics flashing corruption (certain frames) | Seems to be EPROM related, but all of them check good in a reader, so it may well be some of the attached buffers instead. Will return to this one when I have time. Checked ROMs again, multiple pass read - #12 showed up as reading inconsistently. Replaced to fix. This fix dedicated to nolanXL, it's one of his favourite games. |
| Bagman (Stern) | Resets endlessly | I lifted the reset pin of the Z80, to see it jam with coloured blocks all over the place. First decision was to check out the ROMs, 6 of them were corrupted - these are slowly being replaced due to my POS programmer. Oh well, it's traded now for a bootleg Moon Patrol since I needed a working set to diagnose the problem another is suffering. | |
| Battle Of Atlantis | Scramble | Crashing, no sound, player shots solid yellow blocks | Crashing traced to corroded Z80 and socket - replaced both. Lack of sound was down to the amplifier being physically cracked, but both AY3910s were also faulty. Player shots traced to 74LS74 in 10L and 74LS10 in 9L. Also had faulty caps, broken dips, etc... Sold as working. |
| Big Run | Rapid reset loop, rumble motor running on cycle, control lamps strobing, missing sprites. | Bad code ROM on the CPU board was causing the initial boot failure. After this the game would try to run but lamps were still astrobing, test mode was unreadable, sprites missing. By board swapping with a working set the problem remained on the CPU board. On closer inspection found an area of track corrosion due to dirt/moisture, bypassed one definitely bad track and 4 suspect ones, game now fixed. | |
| Big Striker | Sprites flashing on/off each frame and missing bitplanes | Near the middle of the board and close to 4 small SMT customs are two pairs of SRAM, this is the sprite RAM. A quick check showed the chip enable was dead on one bank. Started to look into why and found a small gouge on the back cutting through 5 tracks. Used wire to bypass tracks, fixed. | |
| Biomechanical Toy | Vertical lines through backgrounds and sprites, text corruption | Text corruption caused by broken trace under one of the top layer RAM which someone had previously replaced & damaged. Original fault with vertical lines was a 'flex' fault - caused by a cracked solder join on one of the tile RAM. | |
| Bionic Commando | Capcom 68000 | Background and score/lives display problems - appearing to be drawn twice, halfway up the screen | The small top ROM board was the cause of this, or so I thought. Reseating the ROMs appeared to make the problem go away, only for it to happen again a few minutes later. Actual cause was one of the 3 ribbon cable links between the two main boards - changed them all, problem gone. |
| Bishoujo Janshi Pretty Sailor 2 | Nichibutsu 9195 | No boot, black image displayed | |
| Black Dragon | Capcom Z80 | Character falling through scenery (scenery being mis-drawn I think) | Seemed like ribbon cables at first, but eventually proved to be a heat related issue on the video board. Took a short cut with this one, I had a sort-of working Black Tiger set with a bootleg CPU board and original video board. Simply swapped the video boards and ROMs around - fixed. |
| Black Heart | No sound, no sound effects, dim picture | Dim picture required edge connector cleaning. Lack of sound down to leaked 1000uf/16v cap, two leaked 10uf/16v caps all in sound section, and volume control which crumbled away from the PCB due to corrosion. This left just missing sound effects aside from very quiet 'blips'. Looked at relevant OKI chip and it was trying to do something, address lines active. Most data lines on effect ROM stuck high. Piggybacked ROM with burned replacement and sound mostly worked, replaced ROM to fix samples. Also had to replace ROMs 4, 3 and 7 due to heavy corrosion on left side indicating a lot of time spent leaning on its side in a damp environment. | |
| Black Heart (2) | No sound | Appallingly fitted alternative volume control had broken off and was the wrong rating anyway. Found a replacment on a parts board to match the look/rating of the original. | |
| Black Tiger (bootleg) | Capcom Z80 | Sparkly trailling sprites, resetting, broken backgrounds | Mostly all caused by poor solder joins, the sprite problem was additionally down to some slow replacement SRAMs on video board. They need to be 15ms. |
| Blast Off | Namco System 1 | After warming up sprites would vanish until the connector was pressed on | Actually turned out to be custom chip 39 not having a good socket connection, the connector was close enough for pressure there to 'disturb' it. Lightly cleaned the legs and problem seems to be resolved. |
| Blaze On | Kaneko 16 | Various tile issues in specific places including some attract animation scenes, copyright screen etc. | Doing a 'finger test' on the various ROMs I found the large mask ROM holding the tiles would cause a small pixel line to appear when the pins at the far end were touched, although it did not clear up any problems. Checking the chip with a logic probe, A18 was a dead address line. Traced this back under the PCB and found a very tiny chip in the PCB surface which had broken the track. Break repaired with a solder bridge and sealed with solder mask. |
| Blue Hawk | Intermittent working | All sorts of strange boot failure and crash problems, it seemed like the CPU which is a quad socket type, the socket was bowed with age/heat/pressure. However after replacing the socket the problem remained. Eventually traced to a fractured solder joint on the crystal. | |
| Bomb Jack (bootleg) | Resetting constantly, jailbar backgrounds. | Resetting started after reseating the chips to kill jailbars - turns out one of the ROMs had a very rusty leg which snapped! Jailbar backgrounds was actually a ROM on the top board, which just needed reseating. | |
| Bomb Jack (bootleg) | Black screen during boot, eventually booting to partial background, when coined most of title screen missing (character graphics issues) | Checked the character RAM in 6L, most outputs looked very dead. Replaced RAM but problem remained. Started tracing data lines through stalled buffer chips to a 74LS245. \E on this chip was dead stalling all the data lines, traced to a 74LS08 in 8C. Replaced to fix. | |
| Boogie Wings | Backgrounds missing | Flexing the board got the backgrounds back. Fault eventually (2 hours) traced to a pin on the custom at 11H, by individually checking every pin join on every surface mount chip. The board has *lots* of those.. | |
| Bosconian | Faded colours, bleeding, light bars | This problem affects cabinets that rely on boards to supply VID GND. I simply linked that pin on the JAMMA adapter to one of the common ground pins. | |
| Bouncing Balls | Boots to test menu and stalls (flex issue), horizontal flickery lines across left of screen, intermittent. | Flexing the board carefully would either stall or run the game, located general area and started putting pressure on individual chips. Built quality is very low on this board, one of the PALs wasn't soldered in properly along one side. Removed and socketed - game now running. Sparkly vertical lines were intermittent and would come and go, generally going away after a few minutes. With a fingertip test, located several chips that had an effect - a 74LS04 was common to all of them. Replaced LS04 and problem gone. | |
| Buccaneers (1) | Occasional blocks of sprite on title screen, duplicated vertical sprite line. | The vertical duplicated line of sprite graphic was the original fault, but during diagnosis the sprites vanished entirely aside from a few blocks on the title screen which should have made up the logo. The sprite RAM are two 2148 in U17 and U28, these looked good but scrambling the inputs would result on bits of sprite appearing randomly. Decided to check the inputs, traced to a pair of LS157s in U18 and U29. One of the multiplexed inputs on U18 was stuck low, traced to LS04 in U21. LS04 displaying obvious problems, input good but output stuck low, replaced chip and sprites back to how they were with a duplicated line near the end. Started looking around the sprite ROMs, checked a LS08 at U112 next to them and found a floating dead input on an in-use gate set. Traced this to physical damage under the PCB. Problem fixed. | |
| Buccaneers (2) | Music playing wrong notes, stopping, some samples corrupt. | Both the sound code ROM and sample ROM were faulty, unusual fault but it does happen, given the ability of labels to fall off these games and the cheap ROMs used, maybe it was left in the sun or something. | |
| Buster Bros | Capcom pre-CPS | Green screen | Suicided, revived using Arcadehacker kabuki reprogrammer after recharging the old NIMH cell which was flat but hadn't leaked. Any 3 cell delta peak charger should do. |
| Cabal | Jailbars on sprites, flickering sprites | Flickering sprites were down to a cracked solder join on the interface pins for the top ROM board. Jailbars took longer to diagnose, the sprite RAMs are the ones closest to the front edge of the PCB, 2018s. After lots of tracing I noticed one of the resistor packs used on the address lines had a bent pin, touching the one next to it.. | |
| Cadillacs & Dinosaurs | Capcom CPS1 Q-Sound | Dead | Q-sound battery dead - desuicided both boards to fix. |
| Captain America & The Avengers (1) | Data East ARM6 | Sprites all over the screen | Sometimes you see an intact sprite, then it turns into what looks like a sprite tile dump on a different animation frame. On hold until I learn a bit more. Sent to the parts pile. |
| Captain America & The Avengers (2) | Data East ARM6 | Dead | Seems to be in a reset loop. Sent to the parts pile. |
| Captain America & The Avengers (3) | Data East ARM6 | Corrupt sprites, loud whistle | Corrupt sprites came down to a whole load of lifted legs on the surface mount video chip, middle-left looking from the edge connector. Sound diagnosis started by removing the op-amp which both OKI chips fed, since a strange oscillating voltage could be seen across all inputs/outputs on it. This made the sound stop, replacing the op-amp with a good one returned the tone. Next I lifted each input leg in turn, this showed that while one OKI was making a louder sound, both were doing it. Next I checked the ground for the OKIs, direct trace to common there, so I started to trace the input voltage. I worked back removing filter caps and re-testing, until eventually reaching a voltage regulator with a broken leg. The regulator turns 12v from the edge connector into a 5v feed for the OKI chips. Replacing the regulator fixed the board. Two important notes here: 1) I would have known the input was broken if I'd bothered to scope it before tracing back, saving time. 2) It appears that OKI chips can still function with a missing voltage input! |
| Carrier Airwing (1) | Capcom CPS1 | SROLL RAM BAD | CPS1 base boards are not fun to fix, and this is where the scroll ram is. I swapped on a replacement... |
| Carrier Airwing (2) | Capcom CPS1 | Dead, missing samples, no sound | Was sold as untested and didn't boot. That was fair enough, until I turned it over and saw the 1 inch gouge across the RAM area. It was deep enough that it nearly went through the other side, and the pressure had indeed broken a few tracks topside as well as literally cutting away ones underneath. It took a bit of tracing, but I managed to get the repair down to 4 jumper wires on the underside of the board. Everything else /seems/ secure so hopefully it will last. Then I noticed the samples were missing, I took the boards apart again and noticed one of the pins in the A/B interconnect near the sound, was bent at a right angle. It caused +5v to go to an address line. Straightened the pin, same problem, and then the music died too. I noticed the music would die as the game warmed up, so I started scoping the address lines on the sound CPU/RAM and YM2151, and saw the waveforms drop to approx 0.5v every time the sound dropped out. I decided to remove the RAM first as it was the most likely suspect (and easiest to replace), this made no difference. Next I decided that since the samples kicked in occasionally, it might be the OKI chip which plays them. Removed this (sadly ruined a track while doing so and have repaired it with part of a resistor leg) and carefully hand soldered the new one in. This took a while - 4 sided SMT chip. It also fixed the game, the +5v had probably caused it to go bad. |
| Choplifter | Sega System 1 | Garbled/corrupted sound | Stupid fault - someone had removed and poorly refitted the sound ROM, one leg out. |
| Club 90's | Nichibutsu 8991 | Colour bleed, blue/green | Actually a red fault, 74LS74 in 5N and 5P replaced with 74S74 variants, problem resolved. Common fault on this hardware, cost saving components. |
| Club 90's | Nichibutsu 8991 | Colour bleed, blue/green, pixel corrupytion | As above, additionally needed to fit a 10pf cap in position C26 to get rid of the corruption. |
| Cobra Command | Burning smell, yellow screen | Not sure why (I can't find any evidence of bridging) but 2 SRAMS and 2/4 ROMS on the bottom right of the board shorted internally, generating massive heat. It's possible one of them went initially and took the others with it... Replaced dead ROMs, replaced dead RAMs, board still dead, one big 4 sided custom is getting *VERY* hot still, so I've sent this board to the parts stack. | |
| Combatribes (1) | Sprites = blocks of colour | Sold to me as working, I think this one suffered in transit. Poking around on the PCB revealed that the symptoms changed when the right hand SMT chip was pressured. Checked all pins, found 8 or 9 broken pin joins on the PCB. This fixed it. | |
| Combatribes (2) | Humming, sound drops out and pops etc | Faulty volume control. | |
| Commando (1) | Capcom Commando | Black screen on boot | Initially I suspected the eproms, as two near the security chip had obviously been replaced (U3/U4). These tested bad in a rom programmer, so I replaced them. Board still dead. Had a quick poke around with a logic probe, and noticed that *everything* was dead - all lines either high or low and unchanging. Went to look at the clock section, and probing with an oscilloscope found the crystal was dead. Replaced this and the game started to run minus the music. Music pot was missing... Replaced this and board is now 100%. This was by the way, yet another PCB sold as tested/working which not only didn't work, but even had missing components. FFS... |
| Commando (2) | Capcom Commando | No sound, physically cracked top rom, spites missing bitplanes | Rom was obvious - the lid had cracked off - very odd inside. Be careful when removing roms broken like this because the casing splinters. Sound section was quite obviously dead due to a cap hanging out. Replaced this and the sound came back, but sprites still faulty. Sprites problem traced to a deep gouge in the lowest PCB, cutting 4 tracks near the lower ribbon cable socket. Repaired with wire patches, board fine. |
| Cookie & Bibi's 3 | Semicom | Sound usually not working | Board suffering from a lot of track corrosion to top layer, initially suspected sound ROM corrosion but when probing the ROM after cleaning it, noticed a pulse on the 5v pin. Dry/corroded solder joint - reflowed. |
| Cosmic Alien | Jailbar every 8 pixels, crash on boot | If you see this fault it's very likely one of the 4116 RAM near the edge connector. | |
| Cosmo Gang the video | Namco System 2 | Later levels corrupt, crashes during them | Easy one :-) Someone before I got it had mixed two of the object roms up... |
| Cosmo Gang the video | Namco System 2 | Coin 1 and other inputs failed. | Near the JAMMA connector, you'll see several rows of resistor packs. The one 'on its own' does coin 1 among other things. The joints on this had been bent back and forth too many times and failed. Shaving away resin with a craft knife revealed enough of the pins again to solder it back down. |
| Crime City | Taito B System | No sound | Large filter cap physically broken, replaced it but still no sound. Checked op amps with the scope, nothing but a little noise present. Checked sound RAM and saw activity, but aside from a rapidly flashing A1 the address lines were just slowly flashing - piggybacked TMM2063 sound RAM at IC44 and sound came back. Replaced chip to fix. |
| Cute Fighter | Semicom | Bad colours (including blacks) | Both colour RAM (some Alliance AS7C164) were bad, giving an overall (and strong) tint to colours. Initially Semicom logo screen background was blue-purple, replacing one RAM fixed some colours and turned it to a dark red tint. Replacing the other RAM restored all colours. |
| Cycle Warriors | Jumbled sprites, stuck/crazed inputs, constant sounds | The initial fault was just jumbled sprites. Board turned out to be an undumped version, and while I was looking more carefully at the underside, I noticed two touching chip pins. Bent them apart and the sprites all came back. Unfortunately at this point the music died, then the coin insert sound started to play on repeat, and the inputs started strobing. This gets worse the hotter it gets. Eventually the game stopped booting until it was warm, inputs still stuck but no longer pulsing. I was so depressed I sent it to someone else to take a look at - it's probably the Sony I/O chip which connects to all affected items including a dip switch that stops the clock signal. Update many years later: replaced the Sony CXD1095Q closest to the JAMMA connector, and it's all working now. | |
| Dark Seal 2 | Data East | 4 pixel horizontal dotted lines across certain sprite graphics | I checked the customs and found one loose leg on the character custom, but sprite was fine. Using MAME I zero'd out individual ROM files to work out which chips contained the affected data, which turned out to be MAS-6 and MAS-7. I removed MAS-6 first and while many graphics were drawn incorrectly as expected, the lines were no longer visible. Checked in the EPROM reader and the checksum changed on every read. Burned a 27C800 replacement and fitted in a socket, problem resolved. |
| Double Dragon II (1) | Sound effects FAR too loud, echoing, corrupt, playing randomly | I noticed when warmed up there were moments when this problem went away. Theres a surface mounted OKI sound chip on the board, which I suspected to be at fault, but resoldering the pins didnt seem to help. Replaced this and problem remained. Got very annoyed and resoldered all the track top/bottomside links and the solder joints on every component in the sound section - that fixed it. :) | |
| Double Dragon II (2) | Sound dead, dollar signs across whole screen, messed up title graphics, corrupted+blocky sprites | Dead sound was a missing capacitor in the amp circuit (without it the board just made a loud hum and optionally picked up radio!). The dollar signs and confused character graphics was down to the LS273 (IC32) next to the character rom. Sprites problem came down to two of the 1 mbit 28 pin mask roms on the underside, IC113 and IC114. These can be replaced with 27C1000 roms (NOT 27C010 type). | |
| Dragon Breed (1) | Irem M72 | No sound. | Stupidly simple, a broken cap joint. |
| Dragon Breed (2) | Irem M72 | Some sounds missing, some sprite colour corruption | The middle board is the problem here (verified by attaching romboards to an Image Fight mainboard). I need to get hold of lots of RAM so I can try fixing this. Update: replaced the suspect RAM, problem didn't go away. This now seems to be the same cause for all problems, and relates to inputs to one of the PALs. Update: I wussed out and replaced the middle board with one from a faulty Air Duel - fixed! |
| Dragon Breed (3) (M81) | Irem M81 | Dead, dotted sprites | Before power up many underside crossed pins were straightened out. Next the missing PAL was replaced. M81 boards are very similar to M72, and the M72-8L and M72-9L pals from an M72 board correspond to M81-9L and M81-9P. This brought it to life but the sprites were speckled. Looks like a manufacturing defect was responsible, one ram which looked untouched had one side out of the pcb, just resting on the solder holes. Soldered it in and board was fine. |
| Dragon Breed (3) (M81) | Irem M81 | Some wrong colours on sprites | The KNA91H014 at T9 on the top board (this also corresponds with a similarly placed one on M72 sets) appears to be involved with sprite colour output, the analogue part of. The three resistor arrays next to it, when damaged, appear to affect different parts of the colour output. One of mine was badly cracked - replaced and the problem went away. |
| Dragon Breed (4) | Irem M72 | Certain samples missing including large enemy death sound in stage 1 | This board had originally been a Dragon Breed, and converted to Legend of Hero Tonma. M72 rom boards have several jumpers which I've slowly been trying to document, J3 on the top Rom board being incorrect for Dragon Breed kills those samples. |
| Dragon Breed (4) | Irem M72 | Louder sound effects sort of 'crunchy' | In front of the amp are two small caps - a 1uf 50v, and a 47uf 16v. I replaced both in this instance, but it's probably the 47/16 cooking due to proximity to the amplifier. Same fix now applied to 2 other M72 games, so consider this a common fault. |
| Dragon Saber | Namco System 2 | First sound played (intermittently) would be wrong pitch or missing. | After wasting time looking at the reset circuit, the problem was isolated to the sound ROMs. SND1 verified correctly every time, but when replacing it with the same ROM from a different board the problem went away. Replaced SND1 to fix. |
| Drift Out '94 | Seta SSV | Pink screen and raster corruption, colour imbalance | Being one of the Seta boards with a giant heat sink over a SMT, I knew the graphics would probably be cracked pin joins - seen it before on these boards. Sure enough 5 legs all on the far right corner weren't attached. Reflowed these and the graphics worked, but the screen had a strong pink/red tint, to the point of fringing on some graphics. I had a look at the colour feeds and found an array of transistors, one for each colour and one for sync. Checking with a meter, one of the transistors (green) was showing totally different readings. Replaced all three with brand new ones and the colour balance was restored. Also replaced all the missing 5v filter caps on the ROM board at the same time. |
| DVD21 system | Nichibutsu | Erratic control of DVD player | DVD21 systems use an externally connected DVD player for video footage, controlled by an IR emitter. Some physical damage to the DVD IR board caused a resistor to snap away from the chip legs it was connected to causing al the problems. |
| Earth Joker | No sound | Turning up the volume to max gave quiet and muffled sound - obvious fault, one IC45 failed - a TL074CN op-amp, common fault on this age of Taito board. | |
| Edward Randy - Cliffhanger | Data East MC68000 | Quiet noise/tone behind audio, noticeable when music not playing. | Sound traced to noise coming from one of the OKI M6295 chips (pin 36 is the analogue out), touching that line with an oscilloscope probe was enough to kill the noise completely. M6295 datasheet suggests the use of a filter, DE on this family of boards hook them straight to the op-amp (C3403C) with nothing at all - so if you have a noisy OKI which does happen, the op-amp will happily amplify the noise too. Taking a design cue from one of DEs own boards, I put a 0.0033uf non polarised cap between the op-amp input pin for that OKI, and ground. Noise gone - kind of a hack repair but replacing the OKI chip seems a bit extreme. |
| Elevator Action | Coin 1 not working | This proved hard to diagnose as the credit wiring has already been hacked about a bit - I've heard rumour of a modification needed for these boards, maybe that's what it is. Wired coin 1 up to service switch - problem solved. | |
| Empire City: 1931 | Parts of some sprites transparent | Using MAME and blanking out rom images, I diagnosed the problem sprites as being in rom 18 or 20. Stupidly without checking I cut these both out and replaced them, which fixed it, but while doing so I noticed several of the pins on 18 were sitting solderless in the PCB, and were probably not making good contact if at all. | |
| E-SWAT | Sega System 16 | Sound dead (sporadic life) | Sold as having dead sound, under test the sound would occasionally start working for a few minutes. Flexing the board appeared to make so different, but light tapping did. Checked the 8mhz crystal in the area tapped (just to the left of the sound Z80, but does NOT provide clock signal for that chip), and it was stuck high (presumably sometimes working). Swapped this crystal and sound returned. |
| Exed Exes | No sound | No sound at all from speaker, not even a hum. Suspected amp initially since input was seen and no output, however checked the output capacitors first and found the main sound output cap (1000uf) was completely dead. The sound circuit seems to need this for the amp to output at all. | |
| Fighter & Attacker | Namco NA-1 | Crunchy sound | Namco NA-1 boards have a very common problem with leaking surface mount capacitors. If you are stuck with no boot or bad sound, time to replace them all. |
| Fighting Hawk | Taito L System | Sound effects ok, music gone | Identical fix (even same part number) as Plotting(1) below. Seems to be a common fault on these smaller Taito boards. |
| Final Fight | Capcom CPS1 | Sound effects mostly missing, graphical corruption | Board was supplied with another C board, I was asked to transplant the chip to repair the original. Unfortunately both were glitching, caused by excessive desoldering flux which had seeped into the pin headers from a previous reflow. After cleaning the graphics were reliably good on the replacement C and reliably bad on the original, swapped CPS B chip over - difficult on this game as it's reverse mounted and the connectors get in the way of easy wave soldering. Sound problem was very simple, a bad OKI-M6295 on the A board. |
| Final Fight 3 bootleg | SNES bootleg hardware | Player using super attack automatically on stage start and after throws | This turned out to not be a fault but a design issue. JAMMA specifies that pin pairs 27 & 28 are common ground. The bootleg makers decided that pin 27 should be button 6. End result on a correct loom is button 6 being held down, in this game it's an alternative for button 3 explaining why 3 seemed to function correctly. Very confusing, checking a Bare Knuckle bootleg it has a similar design issue, but isn't trying to read button 6. File this under "when is JAMMA not JAMMA?" |
| Final Romance 2 | Inputs not working, sometimes detected if multiple buttons held | Column driver problem - on this board a SN74LS06N in IC105. | |
| Final Romance 4 | Graphics corrupted, many colours missing | Careful inspection showed a damaged track under the PCB leading to a graphics custom, likely storage damage. | |
| Final Star Force | RAM 3 ERROR | RAM 3 on this board is a pair of 6116 equivalents on the top board, about half way down. I swapped them with new ones and the problem remained. Strangely it didn't complain when no RAM at all was in there, or when just one bank was. While I was starting to probe the address lines, I noticed some physical damage between the two ram sockets. Checking with a meter, sure enough one address line was broken between the sockets, and another worked but looked damaged. I installed wire jumpers between the sockets on those pins, on the underside of the board. All works now. | |
| Flying Shark (1) | Taito Toaplan | Dead | While checking the CPU ram lines, I found a 74LS245 connected to address A7, which if it had a logic probe on it, would cause the game to try to boot (and hang on a sound fault). Replaced the 74LS245 and the problem became worse, now requiring my entire hand bridging most of the pins in that area to get the partial boot. Checking the data pins on the CPU RAM, the traces were noisy and quite unstable. With the probe on one of the affected data lines, I started touching chips to see if anything would cause a response. Touching the sound RAM (a 6116) resulting in lots of trace movement, so I replaced it and a 74LS245 to the right which was causing the same thing. After this, just touching the chips resulted in no trace movement, but the data lines still looked suspect. Touching the data pins on the RAM directly still caused movement, so I used a logic probe on each one, and noticed that address line A1 was floating. I wish I'd checked that before replacing the chips... The sound ROM was also floating on A1, which connects to A1 on the sound Z80. That looked OK, and a quick continuity test showed the track under the CPU must have cracked. Wire jumper repair - game works! |
| Flying Shark (1) | Taito Toaplan | Static interference and humming on boot. | This happened after I made the repair above. The sound section on the board had been worked on before, one mylar cap was missing, and the remaining two had resistors bodged between the leg and ground. I removed the hack and put all 3 caps back in, and the board started to display nothing but a static interference. Removing the caps again, the game booted. Strange. This is the same fault as Flying Shark (2) below. I took a look at a working board, and noticed the sound amp cap had been replaced. Thinking that it might be the cap contaminating ground (which would explain the generally noisy traces I'd seen before), I took it out and tested it - it was only reading 19uf instead of 470. Replaced this with a good cap and the game started booting again. |
| Flying Shark (2) | Taito Toaplan | Static interference and humming on boot, dead 68k, sprite corrption and jailbars | Removed the mylar cap and sound cap, game now comes up with a black screen which is a huge improvement. See fix above for why this works, as it's affected 3 boards now (my worker had already been repaired by someone) I would suggest this is a design flaw on these boards, and a common fault. This board has been worked on a lot in the past, currently the 68k is socketed and totally dead. While checking the connections on the 68k, found one address line with a dry solder joint, fixed this but game still inactive. Wasted loads of time tracing the reset circuit, only to find later that one of the new code ROMs was incorrect. Game started to boot with masses of jailbar and corruption coming from the sprite section. The 2 banks of 3 2148-55 ram had been replaced by a previous owner, pretty sloppy job - found a broken track on one bank of RAM, fixed that but corruption remained and even got worse. Checked out all the data/address lines, then noticed the /WE line on one bank was floating, and stuck low on the other bank. Traced this these through many chips and both ended up on a 74LS08 in E5. Replaced this chip, masses of corruption now gone, corrupt blocks now moving around like the in game sprites should. Testing the two banks of RAM, one is being displayed (corrupt), the other isn't being displayed at all giving a jailbar effect. Need to put a scope on all sprite ROM and RAM now to compare the two banks. Gave up. |
| Flying Shark (3) (Sky Shark) |
Taito Toaplan | Player 1 turning right | Easy fix - tracing back from P1 right on the JAMMA connector, one of the LS240s that handle control inputs was jammed low. Replaced this, fixed. |
| Flying Shark (4) (Sky Shark) |
Taito Toaplan | Unreliable boot, quiet static from speaker. | See Flying Shark entries for background info. Guess which cap was hanging half off, was the wrong voltage, and for some reason was tied to ground with a wire? Replaced this with a correct 470uF/25V cap, tidied up the hackjob where it was fitted, and the game reliably booted. Traced audio with the oscilloscope, the audio was clearly being generated but the amp was hissing. Replaced amp, sound fixed. |
| Flying Shark (5) | Taito Toaplan | Dead | Another total basket case. Applied cap fix as documented above, still dead. Noticed while probing around that some lines on one of the main buses 'fade' to low, blowing in the top right area of the PCB to cool it down makes them die again - I had to do a LOT of fairly invasive isolation work to track the are down though, even cut a track - 17 chips on these bus lines and any one of them could be faulty. I think I narrowed it down to one of two LS240s in the top corner, replaced them both and the slow fade-up seems to have stopped. Game is still dead though so it was probably unrelated. |
| Flying Shark (6) (Hi Sho Zame) |
Taito Toaplan | Dead, jailbar display, jailbar sprites, corrupt sprites, empty areas of sprites, sprites not flipping | Wow, this one had a load of faults. Total lack of activity on CPU, clock signal was dead - traced to faulty 74LS04 in F2. Game now booted, with jailbar corruption over the whole screen and no sprites, sometimes the whole picture would be covered with static corruption. Checked the 6 sprite RAM in the corner and found various signals dead, including OE. This came down to three 74LS08s in D21, D23, E23 and a 74LS244 in D24. Game now had stable sprite jailbars and sprites visibly moving around. Final jailbar fault was the 74LS20 in E27. Sprites were now solid but there was some corruption, traced to ROM B02-04 in D20. Noticed that a small band of each sprite was blank, as the game warmed up this would reduce to a single line. Fault traced to another 74LS08 in C7. Some frames of animation looked 'wrong', and when I tried the screen flip I found out why - the game wasn't able to flip sprites at all so each tile of them was inverted. Fault traced to bad 74LS74 counter chip in 17E. Useful tip for this one, it controls all the OE lines on the collection of 373 and 374 chips, as well as a bank of LS157s so it's easy to spot - hard to trace, I had to cut 8-9 chips from a parts board to trace down the source. Game fixed... |
| Flying Shark (7) | Taito Toaplan | Dead, sprite colour jailbars and priority issues. | I got this booting by accident while inspecting and comparing with another dead one. Noticed someone had put the sound ROM in backwards. Replaced it with a new one and game started booting to a white screen. Saw that the sound RAM data lines were flickering, traced to bad 74LS245 between that and the YM2151. Game came to life but exhibits sprite priority issues in a jailbar pattern. On closer inspection the RAM in the far corner was cracked across the middle, replaced to fix. |
| Flying Shark (bootleg) | Taito Toaplan | Burned edge connector | The top side ground pins on the edge connector had burned to a crisp. The lower ones were OK, but did start to get a little warm if the game was left on for 10 minutes or so. I used some copper adhesive strip, and folded it over the edge to cover both sides where the pins run, then stripped a little mask back from the ground area and soldered both sides to the strip. Seems to hold up quite well which was a surprise, and the heat issues are now gone. |
| Forgotten Worlds | Capcom CPS1 | Would sometimes freeze during the first 10 minutes then start running again | Obviously heat related, this was either a) dry joints on the graphics engine crystal (music was still running) or b) the dodgy join on one of the interconnects. I'm not sure which, I did them both at the same time and it works now. |
| Forgotten Worlds (2) | Capcom CPS1 | Graphical bar corruption, missing tile lines. | I suspected this would be a fault on the LS245s which talk to the game ROMs, and one of them showed an input stuck high. Tracing this to the next component showed that the track was broken due to a small but deep scratch. Jumper wire repair fixed the game. |
| Forgotten Worlds (2) | Capcom CPS1 | Similar to the above again! | Turns out part of the problem above was not fixed, as some problems came back. Touching the surface mount ROM legs made all kinds of corruption appear, noticed 4 legs needed reflowing. Problem fixed. |
| Funny Strip | Player 2 start stuck | Checking at the edge connector, the input was being pulled down all the time, traced to LS244 near dip switches. Cut the leg to check, pin still low, but fine at edge connector, proving the chip was faulty. Replaced and all inputs good. | |
| Future Spy | Sega Zaxxon | Sound effects started to fade away to nothing, some packed up entirely | Zaxxon hardware boards are infamous for this - they rely on cheap capacitor leakage to play sounds.. The missing sounds were caused by IC U23 (D8255) which controls the sound latches packing up. For the fade problem see http://www.system11.org/temp/zaxxon_sound.txt |
| Galaga '88 | Namco System 1 | Music missing | Sold as working, wasn't. I did get it cheap though and a partial refund, so I guess it was OK. Schematics exist for this which made life very easy - the YM3012 outputs music to the op-amps, I could see a signal going into the TL085 in P5, but nothing coming out of the other side. Replaced chip, all fine now. |
| Gallop | Irem M72 | Weak sound, samples either playing too fast, not at all, or repeating | Weak sound was down to one of the 2200uf caps near the volume pot, having a corroded leg. The samples issue turned out to be all three LS191 counters that step through the sound data on the sample rom (IC16 -> IC18) on the top romboard. |
| Gals Panic | Kaneko | Quiet sound, corrupt sprite graphics | Corrupt graphics were caused by one of the customs, almost the entire of one side had cracked solder on the pins, I reflowed that entire side. Quiet sound caused by the PX4460 sil next to the amp, which I recapped. |
| Gals Panic S Extra | Kaneko Supernova | Sound getting more distorted as game warms up. | Seen many Supernova motherboards doing this now. The fix applied to S2 below makes the problem go away, but only for a while - looking at ones with the issue that have obviously been previously repaired. I recently got a much newer variant of SN motherboard, Kaneko obviously realised there was a flaw, as the newer ones have an extra 4.7uf tantalum cap soldered underneath C18 as a helper. Fix now applied to 2 other faulty Nova boards.. |
| Gals Panic S2 | Kaneko Supernova | As board warms up, sound gets more and more distorted, particularly right hand channel | After trying the obvious dry joint fixes, this turned out to be the 4.7uf 25V cap that sits on the feed of the thyristor near the sound amp (which in turn powers the op-amp). Extra info, see S Extra entry above! |
| Gaplus | Board would give 000 boot codes suggesting hardware was OK, but then stop. | After chasing a few red herrings, discovered through piggyback test that this was down to the LS245 near the third CPU ROMs. Strangely it looked fine when probing, I suspect it may have looked wrong during the boot process as the A/B data flow is reversed for a short period. | |
| Gemini Wings (bootleg) | Tecmo Z80 | Dark fading pulsing picture | Looked exactly like a lack of monitor earth and that's exactly what it was. The bootleg board appears to not have this pin (14 topside) connected to anything at all - small trace wire to a common ground point fixed this. |
| Geo Storm | Irem M92 | Some sound effects crunchy and quiet | This board had already been recapped, I noticed that some of the lightning sounds which overlap as they play in the attract screen were quiet and crunchy. There are 5 or 6 quad op-amps on these, one clearly had good input and bad output on one of the channels checking with an oscilloscope. You can use test mode to diagnose this as it will cycle sounds across the 3 effect output channels when played repeatedly. Every third play was bad. |
| Ghosts n Goblins (1) | Capcom M6809 | No Sound | Well, there might have been some very quiet sound, I didn't hear it. This turned out to be the large axial capacitor near the amp section on top board, which had a broken leg right against the side of the cap. |
| Ghosts n Goblins (2) | Capcom M6809 | Jailbars on all the backgrounds and other tiled graphics | Simple problem - two fried roms (they wouldn't even erase) numbers 6 and 7 on bottom board. |
| Ghosts n Goblins (3) | Capcom M6809 | Dead, garbled backgrounds, no sprites, jailbar sprites | Bought untested (expected to be broken) and it was. In fact it got worse after 5 minutes testing too. Firstly the game died completely, no life seen on 74LS04 at 3N next to the crystal. Replaced 74LS04 to get the game going again. NOTE: The timing circuit seems quite sensitive - a brand new 74LS04 wouldn't work, but a much older one salvaged from a parts board worked just fine, as did brand new 7404s. Checked tile ROMs on video board, noticed many of the address lines were stuck and one floating. Traced fault to a dead 74LS273 in 5A, background restored. Checked sprite ROMs next, no activity on CE lines, traced through 74LS139 near memory configuration jumpers to 74LS273 in 8J. No clock signal on 723 traced to faulty 74LS139 in 9K, replaced to get jailbar sprites to appear. Checked RAM at 12N and 7N, both looked normal, started to trace the output lines and found 74LS273 attached to 7N RAM to be mostly dead. Replaced and jailbars gone. |
| Ghosts n Goblins (3) | Capcom M6809 | Sprites missing | Actually found while checking random chips - dead 74LS74 in 2J, without it all the object counters stop. |
| Ghosts n Goblins (3) | Capcom M6809 | Backgrounds missing | V*F lines on the 74LS273 in 10D were OK, but outputs were totally dead, this restored partial backgrounds. Mountains all fine, but actual level tiles missing or appearing incorrectly. Started looking at the tile address section, found that one of the inputs that generates V256S at a LS86 in 11C was dead. This signal comes from a LS74 in 14A which had good inputs and dead outputs. Replaced chip and backgrounds restored completely. |
| Ghosts n Goblins (4) | Capcom M6809 | Sound too quiet at max | Someone had put the wrong amp in this one - should be HA13001 not HA13102. |
| Ghosts n Goblins (5) | Capcom M6809 | Corrupt graphics in last level only | This had to be roms, and gg16 turned out to be bad. Unable to prove the fault is definitely gone because I'm not good enough to reach stage 5.... |
| Ghouls n Ghosts | Capcom CPS1 | Test mode hangs | Game works fine, but set the dips to go into test mode, and it hangs after the RAM/ROM checks finish successfully. I really don't know why this is :/ It's a very low priority fix - maybe it's the PALs, it shares one with Forgotten worlds so I'll try that theory at some point. Sold now. |
| Gladiator | Slight graphical corruption | EPROM QB0-12 had physically caved in - oh dear. Replaced this and took the time to clean off all other socketed chip legs and problem is resolved. | |
| Glass | No sound | Great big hole in the side of the TDA1510. This was sold as working on ebay. | |
| Golden Axe | Sega System 16 | Nothingness, all filter caps broken off | Unbelievably this worked fine as soon as I cleaned the edge connector!! Replaced filter caps anyway, board fine - what an easy fix :-) |
| Golden Axe | Sega System 16 | Crackling sound in louder sections | Capacitor C16 clearly damaged, replaced to fix. |
| Great 1000 Mile Rally | Kaneko AX System | Sound sort of weak and crunchy | Fixed after replacing the sound section caps, half of which were missing due to physical damage. |
| Green Beret | Konami Green Beret | Broken graphics, sound stuck on and corrupt | Graphics easily fixed with replacing one of the roms that had failed, and reseating the CPU. Sound problem was a sticking 74LS253 in 5B. |
| Growl | Taito F2 System | Sound broken up, sounds playing at the wrong times. | While looking up which ROMs held all the samples, I found out which chip did all the sound I/O - surface mount custom TC0530SYC. Checked all the pins, found one lifted - reflowed to fix. |
| Gryzor | Konami Contra | P1 fire dead, P1 jump constantly held down | A common fault on Konami boards of this age is failure of the 74LS253s they use to encode the inputs. P1 fire and jump are both handled by the 253 in position 3E, probed this and confirmed failure - replaced to fix. |
| Guardian Storm | Sampled parts of music missing | Simple failure - these boards have two LM324 op-amps, one of them had failed on this board. | |
| Guardian Storm (2) | Inputs unreliable/not working | If you have an Apples Inc licensed PCB, the wrong resistor packs have been fitted on at least the vertical boards, as a result unless the voltage is cranked up and your loom is perfect, the directional inputs will be messed up. Check resistor packs RA15 and RA17, they should be 102J type not 104J (100 times stronger..). Dip switch resistor packs need changing too, these are right next to the dip switches in the same area as RA15/RA17. | |
| Gun Dealer | Incorrect colours (most obvious yellow skin on title screen) | Picture is assembled via 3 resistor packs fed by LS273 chips connected to the video RAM. One of the input legs on the blue array showed floating, traced to bad LS273. | |
| Gun Frontier | Taito F2 System | Lots of audio noise, initial intermittent freezing, eventual death. | Audio was something I've seen on a lot of Taito boards recently - the 12v filter caps were shot. The freezing error is something this board has always had, I always suspected something wasn't seated right or an SMT pin was cracked, but I could never find the fault. Recently I took it out of storage and lent it at an angle on something for a few hours - came back to use it, dead. Checking around, I did indeed find that one of the SMT legs had a cracked join, reflowed it and the game is running perfectly now. |
| Gun Frontier (2) | Taito F2 System | Graphical corruption, sparkles on intro | Another simple fault, dirty connectors between the boards. PCB was actually sent to me to replace some physically damaged capacitors. |
| Gun Hohki | Irem M92 | Graphical and colour issues, boot delays | Checking with my finger I was able to affect the issues and even cause the game to boot properly by touching one pin on the SMT quads. Identified the exact pin and traced it across the board to a through hole which had been damaged by corrosion. |
| Gundhara | Corrupt sound | This was a Chinese probably unauthorised board from the factory which made Allumer games, instead of mask ROMs it used a larger number of split EPROMs. Sound fault was traced to one sample ROM being stuck in output all the time despite sharing a bus with the other. I traced this to a faulty PAL keeping the /OE low on that chip. Couldn't see any obvious faults on the chips connected to the PAL so I had to bypass it by logically switching the /OE on and off depending on whether the other ROM or RAM were trying to output. Dirty hack and required the use of a spare LS04 input and adding a LS00, but it worked! | |
| Gunforce | Irem M92 | No Sprites | Jumper J3 on M92 boardsets is involved in the sprites somehow, I'm not entirely sure what it does but having seen this same problem twice now I can tell you what will happen if it's missing - no sprites. Position may vary by game, but every game I've seen has it jumped for 'B'. |
| Gunforce II | Irem M92 | Missing synth sounds | Checked output of YM3014 and found sounds, these are mixed by some op-amps closer to the power amplifier - capacitor C211 physically broken. |
| Gunlock | Taito F3 | P2 fire broken | Someone had worked on the board before, including some heavy handed reflowing of surface mount customs. After tidying up a bit found that P2 fire was OK all the way up to the TC0640 custom, which handles all inputs. Replaced with one from a dead Cup Finals PCB - fixed. Additionall VR1 which should never be adjusted on these boards had been replaced. This adjusts a regulated supply for the Ensoniq 5510 chip. This PCB measured 4.2v across that chip, trying to slowly increase it caused the sound to stop working. Set back to 4.2v since it was at least working that way. |
| Gunnail | NMK16 | Incorrect and missing sounds | Previous owner had already replaced NMK004 sound CPU, but for some reason they had also replaced the sound ROM with one from Macross II. With the right data this board worked fine. |
| Guwange | Cave | Text & backgrounds corrupt | I found that the problems would change & strobe when address lines were touched on two of the four mask roms in the bottom corner of the PCB. Checking with a meter I found that address lines 1-7 were broken to these chips, and the problem had to be under U085. Desoldered chip and found breaks were right next to the pads. Exposed some track and repaired with conductive pen, then reassembled. One track also broke on the exposed side, which was repaired with a 2mm single core of wire. |
| Guwange | Cave | Sprite jailbars | There are two surface mount RAM towards the side of the PCB, one of these had cracked solder on a few pins. This fault is apparently not uncommon. |
| Hacha Mecha Fighter | NMK16 | Flashing jailbarred graphics, very quiet sound | Flashing jailbars traced to one of the four 256k SRAM near the JAMMA connector, these seem to be where sprites and backgrounds are combined and probably work in a banking arrangement. Initially deteched with piggyback method, on closer inspection one data line was dead. Quiet sound due to 2x leaking 47uf 16v capacitors on the amp input. Other caps on the board seem fine (no other 47uf present), likely a bad batch. |
| Hammerin Harry | Irem M81 | Corrupt flickering background layers, every second quarter of the screen | I thought this might be a ram fault, but the board self test claimed the ram was OK. Piggybacking the background RAM on the lower board made a improvement though on the one in 8D. Replaced suspect chip and all is well. |
| Haunted Castle | Konami Haunted Castle | Partially readable BAD RAM on colour changing / blocked boot screen, constant resetting. | Board had a LOT of previous repair work mostly of a poor quality, including most of the RAM being replaced and tracks damaged. While looking over the board as it was resetting, I noticed that actually the game would boot and play after about 30 seconds of failure. I had planned to use freeze spray to track it down, but noticed that touching pins on the colour custom caused colours to strobe. That custom contains some RAM, the V shape legs are prone to breaking and pin 1 had a hairline crack. Tiny solder blob on the leg resolved all issues. |
| Heated Barrel | Flickering messed up sprites | A nice easyish fix - there was a pretty vicious scrape on the back of the board that broke 4 tracks near the sprite RAM/ROM - only hard bit was repairing the damage since the tracks are so fine. | |
| Hole Land | Dots only noticeable in certain sprites | Piggyback tested the 8x 2148 sprite RAM, found one to be faulty - replaced. | |
| Hotdog Storm | Flashing and stuck in test mode | This may well be a lost cause. The board is flashing and repeatedly going into test mode - but this seems unrelated to any inputs. In addition, this had soldered roms, and someone has desoldered them all and socketed them into place - badly. Update: one of the LS273s in the top left of the board "influenced" the problem when touched, so I replaced it. Hasn't helped, I think this one is dead, now a parts board. | |
| Hyper Sports | Konami 6809 | Two vertical rows of character graphics appear to be missing a bitplane | I think this is probably a RAM fault - currently studying the schematics to try and make some sense of which RAM it might be. May shotgun it. ROM c11 also diagnosed as failed after noticing corruption on the weightlifter graphic. UPDATE: Replaced c11, weightlifter ok now. I think the other fault must lie in the character ram section. UPDATE: It appears the attribute ram which maintains a table of colour values and character locations is somehow at fault. This is the pair of 2048 RAMs on the middle of the video board. Board no longer owned. |
| Ikari Warriors (1) | SNK Ikari Warriors | Sound cutting out, sprites flickering horribly or vanishing entirely | Sound was bad seating on two yamaha chips. Sprites fixed by renewing faulty board link cable. |
| Ikari Warriors (2) | SNK Ikari Warriors | alternate lines of sprites missing just for some colours | This has been diagnosed as being one of the 2018s on the middle board. Planning to replace ram and see what happens. UPDATE: replaced rams, no change, put this one in the parts pile. |
| Image Fight | Irem M72 | ROM NG 1 2 on boot | This one had worked until the previous owner knocked it over one day. He had then replaced some of the ROMs. The new ones really were bad, putting the old ones in which came with the board made the ROM faults go away.... This left it with a sprite problem (everything was blocks) which is I suspect why the ROMs had been replaced. Checking the sprite ROMs showed the chip enable line was dead, traced this to a bad jumper (J8) which had been bent and no longer made reliable contact. Replaced to fix. |
| Indiana Jones | Sound dropping out on left channel | This is the Namco cocktail PCB set, fault eventually traced to the solder points where the wires to the volume pots go. For some reason Namco made space for them near the sound section, and then ran wires to near the back of the board. Possibly for access reasons when fitted in a cocktail cabinet. | |
| Iron Horse | Konami Double Dribble | Totally corrupt graphics, game running. Controls wrong. | Simple case of the Konami custom CPU needing reseating. These are a very tight fit so be careful when levering them from the socket. The controls being wrong (buttons 1 and 3 linked) was down to someone wire-hacking it into being a 2 button game. Oh dear. |
| Jackal | Konami Double Dribble | Boots to garbage | Managed to get it into a corrupt but readable test mode with the dip switch, sound CPU ROM was bad, sound RAM was bad, colour RAM was bad. The ROM was missing its 5v leg... Replacing this also resolved the sound RAM check. Colour RAM on these is the resin dipped custom in the corner. These are fitted on bent legs, but are quite often slightly squashed at one end by careless operators. That causes the legs to snap at the bend - hard to see, hold them up to the light. This one had a snapped pin in the corner, resoldered and colour RAM ok - all done. |
| Jang Taku | Royal Mahjong | No boot occasionally with stray pixels or sound effect | Battery leaked (very common on these games), which had destroyed the RAM socket. Cleaned up board and replaced socket to fix. |
| Jue Zhan Tian Huang | Loud buzzing noise linked to screen output. | Someone had previously replaced the amp, and socketed the U6612 (a YM3812), and I foolishly expected it to be the OKI M6295 and replaced that too. No change. Noticed one of the capacitors wasn't in great shape elsewhere on the board, turned out to be a filter cap for the Sega sound custom... Problem solved. | |
| Jump Coaster | Slightly garbled sound | Sounded like a vibrato effect on some of the sound, bit crunchy. I suspected the AY-3-8910, but replacing it actually made things worse. Chip almost seemed to be resetting all the time. After doing a lot of probe and scope tracing, I found a signal that didn't look right at all - BDIR on the 8910. This is supplied by a 74LS02, so I replaced it - and the sound got worse. With further diagnosis, piggybacking the new LS02 fixed the problem completely - it came down to the pullup resistor on BDIR, from the factory a 100ohm had been fitted - which pulls the signal up too high. Probably incorrectly fitted instead of by design - fitted a 220 as seen on some of the other 8910 signals, and it cleared the problem up. | |
| Jungler | Konami Tactician | Some sounds/tunes incorrect | Fairly common problem on boards of this age, both AY-3-8910s were faulty, one more than the other. |
| Juno First (1) | Konami Framebuffer | Tripping power supply, graphics | A quick continuity test showed that 12V was shorted to ground. This turned out to be one of the 1000uf 25V caps on the 12v rail near the amp. This repaired, the board came up but exhibited a line of 'sticky' pixels on the screen. Cleaned all pins on the 3 Konami customs at the back of the lower board, problem went away. |
| Juno First (2) | Konami Framebuffer | Sound effects truncated or missing | I suspected a RAM or ROM fault, but the ROM's checked out. One 2114 RAM had failed before, but it made no difference when removed, and no difference when replaced with a known good. Bridging the other 2114 with a known good brought the sounds back to life, so it was replaced. |
| Juno First (3) | Konami Framebuffer | Popping scratchy sound | All three 1000uf/25v caps had cracked solder joins, one was additionally faulty. |
| Kangaroo | Inputs (various) not working | Cleaned edge connector with isopropanol - works fine now :) | |
| Klax (bootleg) | Freezing, bleeding+dark colors | Freezing caused by a substandard previous repair - reworked that and it seems ok now. Colour problems were simply down to the bootleg having no video ground line - added a wire from common ground to pin 14 on the edge connector, fixed. | |
| Knights Of The Round | Capcom CPS1 | Dead on boot, few static graphics | Game had suicided - performed the fixes detailed on the Dead Battery Society pages and the game worked perfectly. |
| Knights Of The Round (2) | Capcom CPS1 | Dead on boot as above, corrupt sprites | After desuiciding the game, corruption was seen on certain sprites, which came down to one of the graphics ROMs. On this board the replacement part is 27C400, non JEDEC chip. |
| Knights Of The Round (3) | Capcom CPS1 | Large text corruption, life bar corruption, character select window corruption, sound randomly dies | The sound fault seems to be related to one or either of ROM 19 and 9, as the problem followed them to a good board. Corruption is tied to C board somehow, note the text on bootup is missing a few colours. Designated a parts board, sold the A board. |
| Kung Fu Master | Irem M62 | Buzzing from speaker | Waiting for an oscilloscope to try and trace this, changing all sound section caps(!) in the meantime. Done all the electrolytic and this only slightly improved - will do the big high voltage resin dipped one next, and the tantalum. UPDATE I never got around to fixing this fully, although I did reduce it an awful lot through extensive recapping. It's sold now. |
| Lady Killer (1) | Occasional graphic corruption and freezing. | 2 cracked leg joins on the surface mount CPU, easy fix. | |
| Lady Killer (2) | Synth sounds missing | This was an Electronic Devices licensed board, they've left the factory like this. Move the resistor in R14 (actually PC, the labelling is out of place) one space to the right, install 0.1uf ceramic filter caps in the 3 empty locations in the resistor/cap row R14 lives in (PC, C? and C10), install 0.1uf ceramic filter above right hand LM324, wire link pins 8 & 9 of LM324 in 5B. | |
| Last Duel | Half the music missing (occasionally heard very quietly) | Physically damaged capacitor CC13 was the cause of this - affecting one of the op-amp circuits. Annoyed since it was purchased from a reputable seller and photos showed it was damaged before they shipped. | |
| Last Mission | Data East Dual M6809 | Not even getting to self test, nasty grungy crackling from speaker | On Last Mission boards there should be a trace wire or two running underneath the PCB. The longer wire running to the ribbon interconnect solder joins had broken off. Careful examination of joins hilighted which one it had come loose from. Sound after investigation turned out to only crackle when turned up. Suspected amp chip, but noticed large 470uf 35V cap was missing (completely) - which is used by the amp chip on many Data East boards of the time. |
| LED Storm Rally 2011 (1) | Scroll RAM A bad, strobing flashing scrambled colours. | Scroll RAM error went away with reseating chips. I found two banks of RAM seemed to affect colours, both had a seemingly inactive chip. Checking the first against a working board showed this to be correct, but the VRAM (two 2018s in 5J and 6J) didn't look correct at all. Surrounding LS245s seemed to be OK so replaced 5J. This resulted in a great improvement but I still had incorrect strobing colours - also replacing the one in 6J cleared up the problem. | |
| LED Storm Rally 2011 (2) | No sample output | Lack of samples (energy pickups, talking computer in intro), fault traced to some cracked solder joins on OKI sound chip. | |
| LED Storm Rally 2011 (2) | Some corruption on scrolled foreground objects | Found some replaced RAM on the lower board, chip had been replaced with another bad one… | |
| LED Storm Rally 2011 (2) | Colours bad (got worse while booting) | Similar to the other board above, RAM in 6J had failed - Sony CXK5814-45L again. I wonder if these weren't up to spec and are being 'worked too hard' as it looked like the chip had been running warm. | |
| Legend Of Hero Tonma (1) | Irem M72 | RAM NG, red output very low | RAM NG was poor seating on the IDC ribbon cables, these are a VERY common cause of RAM NG errors during boot. Check on scope, the red output at the edge connector was obviously weaker. Replaced the colour resister pack for red RA15, no change. Could see that the final output from the RA15 was too low, but the input (looped through a 100 ohm resistor) was correct. The colour lines are also attached to a 74LS38 at IC67, one of the outputs was faulty which was pulling the red down. Replaced LS38 and colour balance was restored. |
| Legend Of Hero Tonma (1) | Irem M72 | Music sometimes playing the wrong notes, looping incorrectly or stalling. | Sound RAM had been replaced, but with Winbond 150ns chips - the RAM speed here does matter and with 100ns ones taken from a parts board the problem stopped. |
| Legend Of Hero Tonma (1) | Irem M72 | More sound noise than normal, impossible to turn volume all the way down. | Obvious fault - the volume pot was rubbish, replaced and noise was reduced, volume now fully adjustable. |
| Life Force | Konami Nemesis | Resetting constantly, black screen | Quick boardswap diagnosis showed this to be a faulty video board - possibly a broken custom. Quick fix for this was to swap in the working video board from Salamander (3). |
| Lightbringer (1) | Taito F3 | Sound intermittently broken - feedback noises, missing speech etc, stuck input. | Sound problem due to someone adjusting the DO NOT ADJUST potentiometer near the amp, this affects the voltage of the Ensoniq sound chip - 4.28v seems to be the sweet spot for most of these chips. Input fault due to 0640-F10 custom chip, replaced with a salvaged part from a donor PCB. |
| Lightbringer (2) | Taito F3 | Sound broken, vertical lines in text layer over all graphics. | Sound problem due to someone adjusting the DO NOT ADJUST potentiometer near the amp just as with the last one I looked at. Corrected to 4.28v restored sound. Graphics error was visible even with the ROM board removed, so I took that off for access. While feeling around and applying light flex, I found an area that affected the corruption slightly. Narrowed down to a pin on one of the surface mount RAM chips near the main GPU - cracked solder. Someone had already reflowed many items on this board looking for the fault. Also replaced several physically broken capacitors, some had leaked from the damage and the board required a full cleaning. |
| Lightbringer (3) | Taito F3 | Bad sound, intermittent | Ensoniq sound chip voltage set to minimum and buried under hot glue - suspect this was done to make it 'sometimes' work, found the sound chip reset cap (22uf/25v) was physically broken on one leg. |
| Lup Lup Puzzle | Quiet sound effects | LM324 closest to the amp showed one op-amp which reduced the effects volume instead of increasing. Replaced to repair. | |
| Ma Cheon Ru | Dead | Crystal had 3 broken legs, sold as working. | |
| Magic Bubble | Jailbars on some graphics | Probed around the board a bit tracing where the sprites were being drawn, problem only affected some types of sprite suggesting a data issue somewhere. Sprite RAM itself working fine but then I found a 74LS244 at U89 which seemed to affect the problem when one pin was probed with a scope. Replaced 74LS244, problem remained. Traced that line off to a PAL with a pulldown resistor array AR7 next to it. When I went to probe the PAL and turned the game on again, the problem was gone. I had bent the resistor array slightly to get better access and read the part number, and this had been enough to fix it. Found that pressing down on the array caused the fault. The reason for this is the resistor array should have been a 6 pin part with 5 resistors. Someone at the factory only had 8 pin ones so they'd cut the legs from the last two. Over time with things being stored on the board this remaining sharp bit of leg had caused a tiny pinpoint hole in the solder mask right above the track leading to the 244, thus pulling the line down. Removed part and really shaved the legs back before refitting - fixed. | |
| Magical Crystals | Kaneko | Very quiet sound | Many Kaneko boards use a PX4460 custom, a small SIL which is resin covered and obviously contains two capacitors, and these obviously fail just like Konami boards. You can get a repro now, or you can chip away / dissolve the covering and replace the capacitors. Replaced to fix with one from a donor board. |
| Mahjong Gal no Kaika | Nichibutsu 8991 | Some colours flickering | Bad colour RAM near edge connector - note not actually faulty, but borderline enough to cause an issue, so swapped it with the work(?) RAM one. Another common fault along with timers on Nichibutsu Mahjong PCBs. |
| Mahjong Gal no Kokuhaku | Nichibutsu 8991 | General screen/colour corruption on certain layers | RAM next to ROM 3 is colour (and possibly work) RAM - removed the game won't even boot, but this chip was faulty. |
| Mahjong Hyper Reaction | Seta SSV | No boot, black screen | Removed the heatsink on the CPU, these often have problems with cracked solder on the legs. Found 7 bad legs, reflowed to fix. |
| Mahjong Hyper Reaction 2 (1) | Seta SSV | Mahjong inputs scrambled | Managed to get it into input test, this showed keys were registering 4 at a time suggesting drive columns on input matrix faulty. Replaced uPA2003C transistor array on ROM board which provides column drives for input matrix, problem solved. Likely caused by being plugged into a JAMMA loom, Hyper Reaction above also had a similar repair. |
| Mahjong Hyper Reaction 2 (2) | Seta SSV | Dim, washed out image | Standard SSV problem, all the picture amp transistors except the sync one had failed, see Q1 to Q4 near the edge connector. |
| Mahjong Hyper Reaction 2 (2) | Seta SSV | No red or green | Q1 & Q2 transistors killed by owner plugging the loom in backwards (easy mistake on these). |
| Major Title | Irem M84 | Sound would cut out as if the CPU had crashed | Ridiculously easy - PAL needed the legs cleaning up a bit. |
| Major Title (2) | Irem M84 | Sound popping loudly, worse if volume turned up. | C203 470uf/25v cap on the 12v looked solid, but tested bad on the ESD meter (no reading at all), and the leg fell off while it was being removed - replaced to fix. |
| Major Title 2 | Irem M92 | Blue and green missing. | Checked underside, tracks leading to picture filter caps had a small but deep scratch breaking two of them. Repaired tracks. |
| Martial Champion | Konami PWB | Sound crackled and died. | This is one of the Konami boards with a sound custom which are known for leaky caps, however - checking the amplifier inputs and outputs showed that the amp itself had failed. Replaced amp, problem fixed. |
| Megablast | Taito F2 System | Wouldn't boot - black screen | After testing it in my cab and seeing nothing, I tried it on my test rig - worked. Tried varying the 5v, made no difference - still worked on one and not the other. Had a look at the board and found evidence of lots of repair work, on a hunch held my finger down on the code ROM data lines and ground, and it booted on all cabs. Suspected cap related, while I was looking at the ROM area, noticed a damaged tantalum cap on the voltage monitor/reset circuit. Replacing that fixed the game reliably. |
| Midnight Resistance | Data East MC68000 | No sound, physical damage. | One of the transistors was broken off, whole board was covered with plaster from where a roof collapsed, couple of caps were wrong or rusty, rusty crystal, etc. Cleaned the board up, fixed the physical issues, leaving me with just the sound problem. Piggyback test showed the sound RAM (2063) had failed. |
| Mikie | Konami 6809 | Sprites vanishing dependent on location, bits of sprite logo missing | Looking at the schematics, I checked the area of the board that appeared to deal with sprite handling. The 74LS163A in position A11 on bottom board which is used for sprite selection, had a failed output. Additional note, undocumented (wire) jumper JP7 S0 is a screen flip for this game! |
| Mikie (3) | Konami 6809 | Constant hum with corrupted screen and semi-broken sync, incorrect colours on some sprite frames. | I started by trying to diagnose the sync problem. This proved quite tricky but eventually following the sync line and all the chips involved in generating it, I found a 74LS161 in B3 with a stuck output - replacing this gave a frozen game still but the picture was rapidly rolling instead of being skewed and wobbling half way up. More checking located a 74LS04 in C1 which is connected to both LS161s that do the sync and vertical positioning, which had stuck on all lines. Replaced that and I had a stable image and no more noise. The game was running at this point, but the graphics were just horizontal lines (vertical essentially, remember this game is on its side), which moved around as the graphics might have been doing. I decided it looked a bit like column 1 of the display was just being copied all the way across the screen, and started looking for things that might control positioning. Checking all the V lines across various chips, I found that several of the ones on the 73LS377 in C8 were doing nothing although I could see pulses on the inputs. I piggybacked a working LS377 but the outputs on that matched the ones on the suspect chip. Checking again and comparing to a known good board, I noticed the pulses on the inputs were different, and scoping them something was obviously wrong. The outputs for the V lines come from a 74LS373 in A8, since piggybacking this with a known good got the signals I wanted to see, I replaced it. Game now visible! Noticed on a playtest that the player sprite was an unusual colour set, and would change colour depending on animation. This turned out to be 1 sprite rom from the Japanese set being on the board. All fixed! |
| Mikie (2) | Konami 6809 | No sprites, jailbar effect on some tile colours | First I tried replacing the sprite ram which is 2x 2148s. This made no difference. Next I started tracing from the ROMs, and found address line A1 was floating. Replaced 74LS86 in D5 which brought the line back up, but now it showed as stuck. Checked the inputs for D5 and found the 74LS273 in D6 which feeds them was also floating. Replaced - 4 fine lines of sparklies now more obvious than before, and address A1 pulsing correctly. On a hunch checked the 74LS86 above the failed one in D5, and found a dead input, traced this back to a 74LS174 in A9. Replaced this and sprites now visible, although corrupted in places including the logo. Started checking the rom address lines again and found address A13 stuck high. Traced this to a faulty 74LS174 in C4. Sprites now correctly arranged, but some parts are transparent. Unfortunately at this point the sprites failed again after 5-10 minutes. I started checking each chip in turn and found a 74LS139 decoder in A7 with a stuck output, seems to be connected to a counter array that generates addresses? Replaced that and the semi transparent sprites were back. I decided since the RAM and ROM address lines were OK, but it looked like a bitplane was missing, that it would be worth tracing the data lines to see where they went. Eventually fault traced to a 74LS175 in F10 which is part of the data line chain between the ROM and RAM. Jailbar effect on some tile colours was a poorly seated tile ROM. |
| Mikie (3) | Konami 6809 | Vertical lines on sprites, sound dead | Vertical lines just due to voltage or poor chip seating (checked both and it went away). Dead sound was the 14.318mhz crystal on the top board failing. |
| Mirage Youjuu Mahjongden | Mitchell mahjong | No sound | These boards use an amplifier which needs an impedence across the speaker outputs, so unlike the majority of Mahjong boards it has a SPK- pin. If you connect these to a normal loom with SPK- being common ground, the amplifier will burn up and fail. Also applies to Psikyo games and some Jaleco ones - CHECK THIS before using a board. |
| Missile Storm (1) | Atari Missile Command | Flashy corrupt bars above and below the game picture. | Game was being drawn correctly, the bars were extra, and clearly were the game drawing memory either side of the video RAM (lower set changed with inputs!). Vertical blanking circuit suspected, this PCB is very similar to an Atari Missile Command board, and while chips are in different locations and some signals moved around, a lot of it is the same. On the MC schematics, page 2 middle left to the right of the 191 counters is where VBLANK* originates, which is used by the video output circuit later on. The 74LS27 in C1 (B7 on MC) looked faulty as pin 12 was stuck low, changing this made no difference which was strange, 12 pulsed normally afterwards. The 74LS10 in D4 (B5 on MC) looked good, and so did the 74LS08 in H3 (J4 on MC) - however, piggybacking the LS08 cleared up the problem. Changed the LS08 and problem resolved. |
| Missile Storm (1) | Atari Missile Command | Resetting, corrupt pixels in display. | Very simple fault - cleaned the ROM legs to resolve this one, happened after moving the cab. |
| Missing In Action | Konami TMNT | Reset on boot with ram error | The 2018 SRAM in C19 was being reported as bad on boot. Replaced, problem resolved. |
| Mister & Miss World 96 | Text colours incorrect, colour cycling effects on logo stalled. | I did a lot of random probe and shorting tests on this until I found the area of chips responsible for drawing the text layer (and it turned out, sprites). Managed to isolate one data line which when shorted to nearby ones caused the colours to flicker the correct and the logo to animate. Traced out the logic of this circuit back to a 74LS273 in UH6 which had a stuck high output. Replaced to fix. | |
| Moon Patrol (1) | Irem M52 | No sound. | The amp was missing... I'm waiting for a replacement part. UPDATE - amp arrived, fitted with a heatsink borrowed from Major Title, board now 100%. |
| Moon Patrol (2) | Irem M52 | No sound, repeated backgrounds | Sound was due to bad seating of chips. The video problem looked exactly like the one exhibited in Moon Patrol (bootleg) below, but all the horizontal counter lines were fine. Further inspection of scrolling video board showed a broken track. Repaired this and all is well. |
| Moon Patrol (3) | Irem M52 | Music hilariously out of tune | Now seen this twice, sometimes when the big AY sound chips on the top board go bad, sound will be intermittent, or out of tune/cut off/all of the above. Replace to fix. |
| Moon Patrol (4) | Irem M52 | Sprites not moving | Another easy fix - bad ribbon cables! Probably causing a clock signal to go astray. |
| Moon Patrol (bootleg) | Irem M52 | Repeating backgrounds | Odd effect, sprites still ran correctly but background repeated several times horizontally. Turned out to be oddly labelled FPU unit on scrolling video board, position 7H. Filing the pins lightly and reseating fixed this. Update: or not.. Now back here awaiting a working set to compare it with. Freeze spray has failed to identify the problem which is now constant. Update: got another set today, used combinations of boards to narrow the fault down to the main board. Checked horizontal counter section on the schematics, and fault traced to one of the two 74LS86s that the counter output is passed through. Fixed! |
| Moon Patrol (bootleg) | Irem M52 | Amusingly out of tune music | On the sound board are 2 AY3-4910 chips. The one closest to the amp appears to do the music generation, and it was being very unreliable on bass tones. Swapped it, problem fixed. |
| Mr Heli | Irem M72 | Tempramental sound, worked sometimes and not others | It turns out that a capacitor is used to delay the reset of the sound Z80 at boot. If the data has not yet copied in before the reset line is pulled low (which will trigger the reset), the CPU can end up booting with incomplete code, and crash. A bad cap here will cause unreliable sound CPU code loading, and the cap in question is the one next to the V30 cpu on the main M72 board. |
| Multi 5 | Spaced out jailbars through some sprite objects | Checking with the probe, I worked out that the jailbar was actually affecting both sprite RAM. By removing each sprite ROM in turn (1-5) I determined that the data in ROM 5 was the only stuff affected, but the ROM itself was good. Since the address and OE lines are all common it had to be something to do with data on just that ROM. Each one has an associated 72LS299 shift register, the one attached to ROM 5 proved bad on piggyback test. Fault resolved when replaced. | |
| Multi Champ Deluxe | Various graphics problems | Checked the huge surface mount graphics custom, found many weak or cracked solder joins - took a while as the pitch is very fine. Still some issues with vertical lines through sprite graphics, traced this to a surface mount TTL chip near the sprite ROMs, not properly flowed from the factory. | |
| Mushihimesama Futari | Cave CV1000 | Blue tint, weak picture output | Similar problem to Seta SSV boards, CV1000 have three AD8061ARTZ chips near the edge connector which amplify video suitable for a monitor - U14 (red) had failed - can be tested with an oscilloscope while in test mode, pin 1 should read about as high as pin 3 - if not, replace the relevant chip. |
| Nemesis | Konami Nemesis | Booting with bad ram reports on OBJ RAM and SCROLL RAM | Replaced what I thought was the object ram, and one other identified RAM on the underside board, but problem remains - although the test screen no longer flickers, so I've fixed something.. UPDATE replaced some more suspect RAM, but possibly with the wrong speed. It's even less happy now. On a lighter note, I now have a Salamander, and I've verified that the top board of Nemesis is mostly alive, although with some input problems (some work, some don't - probably an easy fix). On hold till I can find some known good correct speed RAM (2128-15s). UPDATE: I wussed out and bought a working Salamander, and donated the graphics board from it. The control input failure on the top board was diagnosed as one of the LS253s near the diode array in 3E (affected P1/2 L/R and coin 1/2). |
| Nemesis | Konami Nemesis | Colour balance problem during play, sound resets. | A set of four 74LS09s near the edge connector affect colour balance, two had already been replaced but a piggyback test showed that a third had failed, replaced to correct colours. Sound resets were down to bad contact on the sound ROM socket. |
| Nemo | Capcom CPS1 | Corrupt sprites | Bad CPS B chip on the C board, replaced with a donor from a SF2 variant. |
| New Zero Team | Black screen, no boot | GAL chip is very sick - undumped as far as anyone knows so this will probably be put away until I can find another PCB to try to get a dump from and verify this is the faulty part. Controls OE on the code roms and is doing *nothing*. | |
| Night Slashers | Data East ARM6 | Sparkly dots on backgrounds, incomplete + quiet music | Sparkly dots were down to some very poorly removed and socketed graphics roms - some solder holes were entirely empty. Incomplete sound due to the mono/stereo jumper being missing. However, when the missing channels came back they were very quiet. NS uses 2x OKI chips to generate the sampled parts of the music and the sound effects, one of these had been replaced but it was the sample chip, no problem there. The rest of the music is generated by a YM2151 and YM3012 DAC. The YM3012 is stereo, and while tracing both channels, one vanished on a through-PCB hole. Wire jumper between the capacitor and resistor the track went between restored the audio fully. |
| Ninja Spirit | Irem M72 | RAM NG 7, incorrect sound effects playing / repeating intermittently | RAM NG 7 resolved by replacing reset capacitors on C board, tip learned from Junomans site. Incorrect sound effects down to sample ROM addressing fault - traced to bad 74LS191 on C board, IC17. Came back again with similar fault - all three 74LS191s replaced in total, same as Gallop. |
| Nostradamus | Booting to sprite RAM error on test screen | Expected this to be SMT joint failures, since the board had worked pre-shipping (allegedly). One of the SMT customs had clearly been worked on before, checked pins around the reworked side and nearby corners and found 3-4 pins no longer secured. Heated these up to reflow - game repaired. | |
| Nova 2001 | Resetting, RAM error | Game stuck in a loop on reboot, but when making a video to see it in slow motion, the last messsage displayed was 'ERROR ON CRLRAM'. Using MAME debugger and watch points on RAM areas, I was able to recreate the problem by overwriting test values in the #b000 region, which is sprite RAM. This game has three surface mount 6116 RAM near the graphics ROMs, as well as a large bank of D416C. Again using the MAME debugger I managed to locate the start of the reboot and force the code to loop the sprite RAM check. This resulted in ROM 0 check failure, on this game simply making sure the 0s and 1s add up to the same fools the check, there are 16 bytes of FF and 00 at the top of the file which can be used to balance it out. Finally the game still kept rebooting due to the watchdog. This can be disabled by cutting the track/pin 2 on 74LS08 at 4B, the watchdog input on the reset circuit. With all this done I was able to leave the game running on the affected RAM check which showed clearly that the 6116 at 12K was active. Replaced this RAM to fix the game. | |
| Ojanko Club | Graphics corruption | 2x ROMs had corroded legs that broke off, was able to dump contents and burn to new chips but data matched MAME anyway. | |
| Ordyne | Namco System 2 | Horizontal jailbars through sprites, missing sound effects, weak sound. | Strange PCB, looks like a factory test board. Several chips on the video board were poorly fitted from the factory, one (74LS374 at 7G) so badly that one of the pins wasn't actually soldered in, even gently touching this fixed the jailbars. Resoldered chip. Shooting effect was missing but other sounds were present, and the audio felt 'weak'. Looked over the board a lot and eventually decided to move the jumper on undocumented pins J114, the shooting sound appeared but the bonus item sound vanished. Realised this is NOT A JUMPER, it's some kind of pin header for an audio feed which is not fitted to production boards, whoever later put the Ordyne ROM set on it didn't realise this. Removing the jumper also restored the full body of the sound. |
| Oriental Legend 2 | IGS PGM2 | Battery test fails - boots only occasionally | Not sure why a battery test should make these not boot, they only store scores and time anyway. If you have a PGM2 cart that does this, you need to open the cart up and replace the coin cell (2032 I think). I found it still complained until I set the date and time again, and had to power cycle it a few times working this out. |
| Oscar | Data East Dual HD6309 | Wouldn't boot - black screen | This was sent to me working, but on test was completely dead. I sent it back initially but re-aquired the board recently (some months on). It's amazing what you can learn in such a small time ;-) Checked out the timing circuit (12mhz crystal, 2 resistors, 7404 inverter) - no activity. Replaced the crystal and the board came partially back to life, but with no sound or sprites. Determined that the new crystal was only oscillating on one leg, so decided to replace the 7404, resistors, and crystal (again) in one go, in case one component was causing the other to fault. Board now working. |
| Oscar | Data East Dual HD6309 | Backgrounds incorrect in some levels, displays 'BANK ROM NG' on boot. | During boot, the ROM test claimed the ROM at 10H was bad, but this verified OK in my reader. Looked at the data lines and saw one held high (post-boot) and one held low (all the time). Checked with a meter and it appeared to be shorted to ground, despite having a track leading to a 74LS74 just above it. Removed ROM, pin still shorted to ground at the socket, cut the leg on the LS74 and verified that it was shorted to ground in that chip. Replaced 74LS74 and ROM now good on boot. Graphics problems resolved. |
| P-47 (1) | Jaleco Megasys | Stuck in test mode, buttons appearing to be held down | Megasys (P-47, Rod-Land, Saint Dragon, many others) can be sent into test by holding down P1 and P2 coin switches on boot. This is now fixed, please see Saint Dragon (1) fix... |
| P-47 (2) | Jaleco Megasys | Player explosion and some other samples missing | Samples are played by two OKI 6295 chips on the ROM board - oscilloscope showed both ouputs were playing, these go through two 10uf/16v caps, one was faulty. |
| Pac-Land | Namco Pacland | Screen of garbage, no boot, wrong colours, flipped character graphics, corrupt sprites, no sound, sprites jump back/forth when moving. | I started by checking some of the main RAM address lines, A8 was floating, this was traced to a broken track near 10J. Corruption pattern changed slightly. Decided to try replacing the HD68A09 in 8A, game booted to a corrupt, miscoloured title screen. Colours seemed to be lacking all red, replaced colour PROM in 2T to get all colours back. Next I decided to check the backround ROMs, found another dead address line on pin 3 of the ROM in 7T. Traced back to faulty LS174 in 7R - replaced and backgrounds still incorrectly drawn but now stable. This left me with corrupt flickering sprites, and the whole screen was upside down, character line by character line. Checked bank of ROMs starting 8J next, found stuck line A13. Traced to bad LS174 in 6K, and in turn from pin of that to a failed LS139 in 10B, not sure what this fixed.. Checked sprite ROMs next, found dead address line on pin 6 of the set at 6/7/E/F, traced back to faulty LS86 in 9C. This removed the rest of the corruption and also fixed the mirrored character issue (9C is a quad some of the FLIP lines run through). Sound problem was easier, the large filter cap was missing entirely and the amp didn't even hum - replaced both to fix sound. Final graphics issue with sprite horizontal positioning was a broken data track somewhere between the 74LS245 in 8P and the custom in 2R, which is part of an 8 bit positioning bus. |
| Pang | Capcom Mitchell | Dead | Another suicided one - dead easy to fix! |
| Paradise | Slow sound, noise + drop outs | The noise and sound drops were a bad volume control. Sound was playing too slow since someone had put a 3.5mhz crystal where the 4mhz one should be which drives the sound CPU! | |
| Perestroika Girls | Sound fault, boot to corruption | Sound fault (rumbling) only appeared while I was checking the boot issue - amp nearly on fire, scolding hot. If this happens check the 220uf cap near it is connected - replaced cap and amazingly the amp still worked... Boot issue down to 10uf 16v cap in the middle of the board - part of the power on reset circuit. Was obviously damaged, one leg nearly pulled out. | |
| Phoenix (bootleg) | Sparkly sprites, no music, no screen flip | Sparkly sprites was just down to RAM seating in sockets. No music was the tone generator having failed, replaced MN6221 to fix. Screen flip traced back as far as a broken 7416 inverter, but on further inspection that output is being held low even when working due to some strange repair work which includes a wired in chip. I need to compare this to schematics and try to restore the board properly. | |
| Pinball Action | Dead, repeating sound | Disconnected the 12v feed for the moment since it's resetting and the amp is getting very very hot indeed. It has been suggested I should check the caps. | |
| Piranha | Lines under sprites which go away after warming up | Using freeze spray I found that one of the BPROMs in 4A had weak output, replacing this solved the problem. | |
| Pistol Daimyo | Namco System 1 | Vertical spotted missing areas of sprites | Caused by fault TMM2015 RAM in position E4 on the cpu board, diagnosed via piggybacking. |
| Pit Fighter | Didn't boot, blank screen | Poking around and flexing the board lightly showed this to be a flex related issue. After careful inspection, one of the resistors used to turn crystal output into logic high/low had *no* solder on one leg. None at all, looks like it had always been like that from new too. Soldered leg in, board fixed. Amusingly looks like someone tried all sorts of resolder jobs on it and never found the problem. | |
| Plotting (1) | Taito L System | Sound effects loud, music faint and crackly | Still working on this, replaced all the caps with no results, and I suspect it's the dual op-amp (C4556C) or DAC (Y3014B) at fault. Bought an oscilloscope, after a tough new learning experience I've narrowed the fault down to the C4556C, it's dead on the A outputs I think (or at least very ill). UPDATE - replaced 4556. After a briefly exciting pyre of smoke coming from the big amp filter cap (my fault, mixed polarity) this board is now fixed :-) |
| Plotting (2) | Taito L System | No video sync | PAL has gone. It's shorted sync output to ground, which isn't a good thing, I need to get a new one made, if possible. Now used as parts. |
| Plus Alpha | Jaleco Megasys | Positional sprite glitches | Spirites glitched depending on location, causing stray pixels or short lines here and there. Via piggyback testing discovered this was caused by a M5M5256 RAM in position 2D. |
| Popeye (1) | Nothing (no roms) | This one arrived with no ROMs, sold to me as a Donkey Kong Jnr (thanks guys...). I made a full romset for it, and an image appeared, but it was just gibberish. Two Popeye sets exist, if this happens to you, reburn the 4 code roms from top PCB with the unencrypted set. Game seemed to work (though without sound and with inverted video since it's a Nintendo PCB) but then died again after 20 minutes, causing 2 large bars of background graphics to vanish. Diagnosed this as a faulty 2016 RAM on the video board, replaced with a 2128 (also 2k x 8 format) and this seems to be fine. | |
| Popeye (2) | Screen full of garbage | Checked the code ROMs first, 7E wouldn't realibly read at all - replaced and the game booted. | |
| Popeye (2) | Resetting | Noticed the game would reset when the code roms were touched on certain address lines, isolated which one and traced it to a nearly 74LS139. Touching pin 9 resulted in a reset, piggyback test resolved the problem - chip replaced. | |
| POW (1) | SNK 68000 | Another with poor sound | Again this was solder joint problems on big caps - seems lots of people out there aren't very careful with boards... |
| POW (2) | SNK 68000 | No sound at all | Nice easy fix - after a quick poke around I found that the amp legs were corroded and a couple had all but snapped. New amp chip fixed this. |
| Power Drift | Sega Y Board | Some frames of animation missing | Checking the roms, it seems that the CPU 3 code ones are slightly corrupt - I expect replacing these will fix it, haven't had time yet. Update: sold the machine, replaced the rom before it was taken away, problem resolved. |
| Power Spikes | Intermittent total failure | Lightly flexing the board proved to fix or aggravate the problem, so I decided to first check for chips with suspect solder joints. As luck would have it - a very light twist on the RAM in position 121 seemed to be the key. Resoldered the joints on this, problem solved. | |
| Psycho Soldier | SNK Ikari Warriors | Game running, but no backgrounds at all | First I checked the tile ROMs (bottom board, P13-P16), but they looked ok. Next I tried reseating all the PALs. No effect. Next I took a look at the clock circuits - fine. Next was the EPROM chip select (OE/CE) lines - they were all stuck high (off). Traced this to the 74LS139 in B5, sure enough this wasn't trying to select chips. However, the enable line on that was also stuck high (off). Tracing this back through a series of LS273 inverters finally led to one which had a floating output (but pulsing input). Chip replaced, backgrounds working! Fucking good thing too as that board cost me a bloody fortune untested ;-) Update Of course 10 minutes later it failed again during soak test. Two of the other LS273s that talk to the tile roms developed problems, so I got annoyed and replaced both of them, plus the 4th one. All problems now resolved. I suspect the initial faulty one got "zapped" at some point before I got it, and the others suffered residual damage. |
| Puckman Pockimon | P1 inputs erratic | Checked P1 inputs and the high signal was barely registering, but they were pulled low reliably. Noticed the 5v pullup resistor pack for P1 was missing from the factory... | |
| Pushman | Jailbars on half of foreground objects | Since I had 2 boardsets here, this was quickly isolated to the top board. Performed finger test on the RAM, and two of them resulted in the foreground graphics scrambling when some of the address lines were touched. Probe showed no signal, traced both to 74LS175 in IC117, replaced to fix. | |
| Puzzle Break | Semicom | Strobing discolouration on certain colours, fault would get worse as game warmed up. | This was a strange fault which looked almost like the output of an interlaced game except for some black areas which were strobing a dark green. Having seen problems with Semicom colour output before I started by checking colour RAM and surrounding components and found a 74LS374 in UA13 which when probed on one pin changed how the fault appeared. Using freeze spray on this chip drastically changed impact of the fault so I replaced it. No change, in fact probe no longer affected the fault. Traced where the line went, and it turned out to be data line 0 from one pair of video RAM, via a 74LS245 in UB14. Since piggyback tests on the RAM seemed to make no difference I suspected the 74LS245 and replaced it. No change. The data lines also went through pullup resistor array RA2 next to the 245. Noticed the resistor array had been fitted backwards at the factory. Removing and refitting fixed the problem. Amazing this had never been looked at by the factory or operators, probably didn't care. |
| Rad Rally | Sega System32 | No blue in video signal | Tracing from the edge connector the source of R/G/B on these boards is a Sega colour mixing / DAC custom, the 315-5242. This is a custom module with surface mounted parts and a resin dip similar to Konami sound customs. Each colour has a resistor and a small transistor fitted. Measuring resistance between the various pins of the transistors showed that the blue one had very different measurements to green or red so I suspected this to be faulty. On a Japanese wiki page I found a photo of a module with the coating stripped, transistor type B24, on a lookup chart this is a 2SC3734. Removed the suspect part and fitted a new 2SC3734 and colour was restored and balanced against red/green. Be careful when trying to remove the old part as it would be easy to pull away the solder pads. If unsuccessful, Caius sells replacements for this module now. |
| Raiden | Flickering sprites, garbled background tiles, corrupt character graphics and logos, no sound, freezing | Oh dear, this was in a sorry state. First I fixed the sprites, this was down to the pin connectors on the daughterboard having fractured joints. Next, the background tile problems came down to a damaged track under the tile roms. The lack of sound was traced to the nasty resin covered custom op-amp effort between DAC and main amp. Luckily Dead Angle uses the same one, so I welded the new one on (nasty job). The corrupt characters (letter M for example) and logos came down to a both the character roms being faulty. Freezing was resolved by replacing corrupt code rom #4 and reseating the main CPUs (lots of times). | |
| Rally Bike | Certain sprites (not image related, but sprite used) missing blocks of 8 lines | Visual inspection found several tracks with the mask scraped off, one of which was broken (bottom right, near sprite ram). Wire fixed this and it's fixed now. | |
| Rambo 3 | Taito B System | Screen showing only partial sprite areas in solid colours, rastering near the top. | IC47 (2018 SRAM) is the colour RAM for this game, it showed some very weak pulses on a few of the data pins. Piggyback test caused obvious (although partial) improvement. Replacement fixed the board. |
| Rastan (1) | Taito 68000 | Inputs glitchy, have to hold down buttons for others to work | If you trace the input lines of these boards, you'll find a collection of LS251s. One of these had failed and been replaced previously, but the repairer had managed to break the grounding pad on it, leaving the chip groundless. Wire-patched the leg to ground, controls fine. |
| Rastan (2) | Taito 68000 | White screen | Another pointlessly easy fix - this just had a missing rom.. On replacement it worked but the sound was very weak - this was traced to capacitor C23 also not being there. The filter caps were all missing too, and the H connector shorting jumper. Don't these people ever take care of their boards?? |
| Rastan (3) | Taito 68000 | No sound, rising hum on startup which cuts out. | Checked the YM chips and found that the music is definitely playing. Next checked all the caps with an ESR meter but no luck. Op-amps looked OK but the sound seemed to vanish just before the volume pot. At this point I accidentally shorted the pins on the final output stage of the op-amp section (IC106 pins 5-7), which tripped the power supply - after that the rising hum was gone although everything else remained the same, with VERY faint sound at maximum volume. Explored a bit more and eventually decided it had to be IC106 at fault since no amped sound could be seen on the output anymore, previously there was a tiny amount of trace movement but obviously that section of the op-amp had already partially failed. The chip is a TL074, I only had TL084s (turns out these are a lower grading of the same component), and this restored all sound. TL084 are noisier than TL074, will replace with the correct part as soon as I get one. NOTE - schematics are available for this game! These helped diagnose the op-amp section no end. |
| Rastan (4) | Taito 68000 | Very quiet sound, corrupt character graphics | Graphics issue was a failed ROM in the character bank, I had a full set on a scrap board so this was a nice quick test. As with Rastan (3), IC106 (TL074)had failed. Replaced with a TL084 and the sound came back, but with a horrible loud whistle. Found that this whistle got much worse when the other TL074 was touched. Replaced second TL074 with a TL084, whistle gone, all OK. |
| Rastan (4) | Taito 68000 | Sound corrupted and died during play, game froze. | Testing showed that the game would run but crash frequently, if the board was left off long enough the sound would work for 10-20 seconds and the problem would return. Used a lot of freeze spray hunting this down, turned out to be the Toshiba sound RAM at IC50 crashing the CPU. Not sure how this can freeze the whole game, but it can. |
| Real Break Billiard Academy | No sound, graphics/colour corruption. | Sound was simple enough, 2 missing SMD caps in the sound section, one of them fell out of the antistatic bag when it arrived (note - sold as faulty). Graphics problem was harder to trace, ended up checking all surface mount TTL chips and found a poorly looking LS157 output. Changed this chip and the colours stabilised (previously shifting and bleeding on and off the screen). Remaining problem looked like a missing bitplane on tiles, traced to another LS157 which was stuck high. | |
| Red Hawk | Background layer shifting position and stretching horizontally at random, random sprite corruption when cold / low voltage. | Really strange looking problem, the board came with a note on it saying 'adjust 5v' and I found that running it under voltage made the problem go away. For a bit. Eventually decided it was heat related, and after working out which FPGA was drawing backgrounds I noticed one of the pins caused the problem to get worse if touched. This turned out to be a red herring! So, skipping the pointless repair the problem came back to the timing circuit - a 74LS04 and 74LS74 next to the crystal. Changing surrounding support components changed the problem without definitively fixing it, the clock signals were 'wrong' in some way. The 74SL74 looked bad though, replacing that made the problem better - and replacing it again with a different make of chip resolved it completely. Suspect the real culprit is the 74LS04 being borderline, as it was common to every potential fix even though the output looks good and freeze spray made no difference after the LS74 was replaced. Interesting note someone had fiddled with the LS04 on my US board I was using for comparison before replacing a cap, so it seems this problem might be fairly common. Additional problem some sprites glitching when at lower voltages until warmed up - particularly obvious on the ship select screen. Freeze spray very quickly isolated this to one of the sprite RAM, replaced to fix. | |
| Renegade | Graphics corrupt, flickering | First I cleaned the masses of solder off the edge connector (I still can't see why this was done, they just made the pins MUCH thicker - too thick in fact). This didn't fix it, but did at least mean the loom could fit properly. The actual problem was bad seating on the ribbon cable interconnects :-) | |
| Ring No Ohja | Konami | Speech and samples playing slowly | This game has a 640khz resonator on board, which someone had replaced with a 490! |
| Road Fighter | Konami 6809 | Corrupted display, and odd wired-on hack | FIxing the display was pretty easy - just reseated the ribbon cable links between top/bottom board. The hack was strange, someone cut the video sync track and passed the sync through an inverter piggybacked onto another chip. I suspect this was done to run it in a strange or VERY old cab, removed the hack and repaired the track. |
| Road Fighter | Konami 6809 | Corrupted unstable "bleeding" display, weak output, missing colours. | Using finger test as the corruption was very active, founr bad 74LS174 on lower board, near left hand ribbon connected to the LS241. |
| Roc 'n Rope | Konami 6809 | Horizontal (vertical in real terms) jailbars across character graphics and black background. | Noticed that the jailbars vanished when ROM 6 on the main board was nudged. Cleaned the legs, no change - had to replace the socket in the end. Also replaced physically damaged and leaking caps on the sound board. |
| Rock 'n Rage | Graphical problems on tiles, hacks and wires on inputs | Graphical issues had been worked on before, checking the address lines on the tile RAM I found that one address line was dead. This was directly traced back to a faulty 007342 graphics custom, which had to be replaced. The wires and modifications all over the inputs were an ugly attempt at fixing them. Once all the hacks were reversed and new optos installed (legs had been cut) I found that pressing p1 right also toggled other buttons. Checked resistance between button inputs and found that pin and other affected ones had low resistance between eachother compared to others. Faulty 007325 discovered which is a SIL custom part which is actually just an 8x diode array. | |
| Rod-Land | Jaleco Megasys | Boots with blocks of colour and hangs | Bottom board looked to have been stored in water, but the ROM daughterboard appeared to be fine having tested it on another Jaleco mainboard (from Saint Dragon, P-47 would also do). I need to get a spare mainboard.. UPDATE - see Saint Dragon (1) report, Rodland now has a base and is 100% |
| Rolling Thunder | No sound on some setups | Suspected this was to do with the difference between grounded audio and non grounded audio looms. Measured amp output pins and found signal on both, traced this to a damaged through hole near the edge connector. | |
| Rolling Thunder 2 | Namco System 2 | Sound hissing + crackling at low volume | Someone had tried to fix this before, I reflowed the large sound cap which is a common fault and was cracked - no change. After lots of probling around it seemed that one of the TL084 was the problem - replaced and no change. Scoped some parts of the audio path and found a sine wave on 12v - through long process of elimination eventually found a faulty cap C53 which had leaked but not enough to be visible. |
| R-Shark | Flickery corrupted/misplaced sprites | This was some kind of board flex issue - pressing in certain areas of the board would clear the problem up while running. After a LOT of time with a multimeter this was traced to a track link where one connects from topside to bottomside, in the sprite hardware area of the board (left hand side if connector is facing you). | |
| R-Type | Irem M72 | ROM NG on boot | Previously this had been a working board, but one day it came up with that message. All the roms read as ok in a reader, and the two TTL chips on the romboard also looked ok. The mainboard and baseboar dverified ok with a romboard and roms from an Air Duel, so tracks were suspected. These also drew up a blank, so I bought a working R-Type and tested the romboard on the problem boardset. Game ran fine. Individual swapping of roms eventually traced the issue to a romchip with a jammed CS line! |
| R-Type (2) | Irem M72 | Blocky corrupt sprites, blocky backgrounds. | I got this and a dead Hero Tomna at the same time. This was reporting RAM NG 4 so I put the Tomna board on and the backgrounds turned blocky.. That was traced to a bad ribbon cable, leaving just the sprites. I established that the top board was at fault by putting it on a known working set, and checked the ROMs. One was bad, looking at it the window was cracked too. Replaced, fixed. |
| R-Type (3) | Irem M72 | RAM NG 5 (sound working intermittently) | RAM 5 is the sound RAM near the Z80, replacing this had no effect. Since the problem happened even without the sound CPU installed, it had to be something between the main CPU and RAM 5 - looking at the schematics there are a number of buffers used for address and data access, but I decided to focus on the data since it looked like it would often report bad even though the sound worked, suggesting the read/write was inconsistent. IC41 (74LS245) carries the lower data lines so I started with that one, despite a piggyback test making no difference, replacing the chip fixed the board. |
| R-Type (4) | Irem M72 | No text or foreground tiles | M72 boards have two tile layers - the B boards are almost symmetrical down the middle, the side with the surface mount chip does the bottom 'B' layer, the other side does the foreground 'A' layer with additional priority control. Since there was plenty of activity on the associated ROM and RAM, I decided to start tracing from closer to the output stage - the surface mount chip overlays these layers and outputs the analogue signal, so I started by checking the A side inputs to it (BIT1A etc). These were dead. While they pass through a few chips (LS157/LS175) on the way, these signals are generated by the KNA6034201 custom chips IC3 (A) and IC3 (B). The outputs from IC3 were also dead. Next I checked the data line sets and found them to mostly be active - the chip was talking to the ROMs. The only other inputs of note to that chip are two clock signals, the one on pin 17 (SLDA) was stuck high. Checking the schematics, this is generated by a 74LS175 IC60. Checked operation with that chip removed in case another in the chain was pulling the line high, and found something was, and the signal was shorted to 5v somewhere. SLDA goes from IC60, to IC3 and a pair of LS166s IC5 and IC13. I started by snipping pin 15 on IC5 and immediately the short went away. Replaced LS166 and text/tiles came back to life. |
| R-Type (5) | Irem M72 | RAM NG 3 or 4 | No actual fault on this board, problem was seating of ribbon
cables which is a common issue on these boards. Correction, completely unpredictable
intermitted fault - has at least been isolated to video (B) board through
swapping with another boardset. |
| Saint Dragon (1) | Jaleco Megasys | Player 1 button 1 dead | Jaleco megasys boards use fragile tiny little daughtercards on all the input lines. The pins on these break constantly - this was one of those occasions, with some care solder can be used to bridge the pin breaks. Note that Caius now sells replacements for these parts. |
| Saint Dragon (2) | Jaleco Megasys | No Sound | This was 'something' on the base board at fault - so I replaced it with one from a Takeda Shingen. |
| Saint Dragon (2) | Jaleco Megasys | Some sound effects missing | Appeared to be top rom board related - but was not the roms. Probably a failed OKI chip but used a donor board to fix this one from a Takeda Shingen. |
| Saint Dragon (3) | Jaleco Megasys | Corrupt sprites and backgrounds | Checking the roms, this came down to roms 12, 14, and 17 for the background. Strangely the sprite roms all read ok, but testing with some known good replacements, rom 21 was shown to not work in the board - someone has suggested this means it had a faulty output enable (OE) line. |
| Saint Dragon (4) | Jaleco Megasys | Control inputs dead | I expected this to be the resin covered customs along the edge, and indeed it turned out to be controls handled by the middle of the three. Checking the pins on it which are prone to snapping, the 5v pin had snapped, as had the ones for P1 up/right/fire1/fire2. Fixed these with solder bridges but P1 down/left were still broken. Checked the inputs and they looked fine. The outputs connect to a 74LS245 bus transciever. Since other outputs for controls that worked connected to the same pins as the faulty ones, the LS245 I decided was OK. This meant the fault must be the custom, so I replaced it with one from a faulty Takeda Shingen motherboard. All controls restored. |
| Saint Dragon (5) | Jaleco Megasys | Corrupt samples in music and gameplay | Corrupt samples in music: OKI closest to the 5/6 ROMs. Corrupt/wrong sound effects: the other OKI... Replaced both and board repaired. Common fault on these boards. |
| Saint Dragon (6) | Jaleco Megasys | Text incorrect, screen filled with partial characters | Suspected some kind of text ROM addressing was incorrect, the text ROM on this game is ROM 19, this is talked to across connector #6 on the ROM board. Under the ROM board there are 3 VCTR video chips each connected to one of the connectors 4-6. Checking the connectivity from the VCTR to connector 6 I found that one of the tracks was not connected to the expected pin, verified by checking a known good board. Reflowing the pin didn't help so the track fault must be under the connector itself. Fixed using thin kynar wire and using a through hole from an unpopulated chip as a route from lower to upper side of the board. |
| Salamander (1) | Konami Nemesis | Booting with corrupt screen | Please see the Nemesis report above - this has a known faulty graphics board with RAM problems and is on hold till I get that far down the priority list ;-) Now also has a faulty top board (2 x LS253s) see Salamander (2). No longer owned. |
| Salamander (2) | Konami Nemesis | Coin inputs dead, p2 fire dead, p1/2 bomb dead (all stuck on) | Quick and easy diagnosis, this was the LS253s in 4D and 4F. I was feeling lazy so simply swapped the working one from Salamander (1) on. Fixed. |
| Salamander (3) | Konami Nemesis | Resetting constantly, light blue flashing screen | This has a faulty top and bottom board now, see Life Force. No longer owned. |
| Salamander (4) | Konami Nemesis | Stuck 1/2 coin, various fire buttons | After much diagnosis and replacement of other parts, this turned out to be a fault in two of the octos that sit beteen the edge connector and the LS253s (that are usually the problem). Identifiable by voltages being out of spec on the affected control lines. |
| Salamander (5) | Konami Nemesis | Stuck p1 & p2 missile buttons | Looking from the edge connector, this was due to the two right side optocouplers, NEC2401. Replaced with equivalents TLP521 (PC847 will also work). |
| Salamander (5) | Konami Nemesis | No sound / hum / white noise | Various versions of no sound at each boot. Checking the sound chips there was no activity at all, and looking at the Z80 there was no reset signal. Traced reset problem to faulty 74LS244 below. |
| Samurai Nihon-ichi | Boots to garbage, missing sound effects | Z80 was getting very hot, replaced - red herring although new one ran far cooler. Checked data lines on the three code ROMs, noticed some stuck high. Removed ROMs and newly socketed Z80, still high on 2 data lines while the rest floated as expected. Traced to bad LS245 nearby. Game now ran but credit and death sounds were missing, while other sounds were fine. Sound board has 1x AY8910 which plays the music, and two Z80s which handle some sound effects each. Sound came back to life during diagnosis, suspect removing and replacing the ROM fixed it. | |
| Samurai-Fighter Shingen | Jaleco Megasys | No sound, missing samples | This worked until the donation of its baseboard to Saint Dragon (2), also now also has a faulty romboard, one of the two OKI chips (the lower one I think) is sick. Checked RAM on sound 68k, no activity at all. Checked 68k - absolutely dead. Piggybacked 68k and saw activity, cut out and replaced but still no sound. Next I replaced the two RAMs connected to the 68k and the music came to life. Samples still missing, checked the OKI chips on the romboard and found that one was dead. Replaced this and all sound OK! |
| Sand Scorpion | Kaneko16 | Sound very quiet | Suspected amplifier as no hum at all, sound barely audible at maximum volume. Replaced amplifier, no change. Kaneko sound sections have two potted custom modules, one will be attached to the amp and contains two surface mount caps - this part was faulty. |
| Sankokushi | No boot, freezing | Board would boot one time in 10, and then freeze with the slightest provocation. Someone had obviously tried to fix it before and made many needless and somewhat messy repairs - but probing the CPU work RAM showed that one of the data lines was intermittent - bad solder joint. | |
| Saturn | Failure to boot, corrupt blocks of graphic | Roms 5 and 6 on Saturn boards are on a tidy riser board which plugs into socket 5. The riser board had several broken tracks and ones that tested ok sometimes but not others. I wire linked a bypass on the tempramental/broken ones, and it works now. | |
| Sauro | Intermittent non-boot, sparkly pixels on sprites at cold, pixel level colour instability | Intermittent non boot was due to a missing capacitor C2 (10uf/16V tantalum), the track leading from a nearby resistor to it was burned away, and it had been bypassed with what was left of the track, possibly a mistake. Repaired track and put new cap in to make reliable. Sprite sparklies located using a freeze spray on the sprite RAM, found one bad P2149H-2 RAM. Pixel level colour problems took a while to find, initially checked colour RAM but found from the MAME driver there are multiple colour RAM sections, the problem if you looked carefully affected certain types of colour on sprites and both tile layers, so I decided to check back from the picture output on the edge connector instead. These go to a resistor array, and then to some 74LS174s, one of which was obviously bad when piggybacked. | |
| Scramble (1) | Konami Scramble | Boots with corrupt screen and appears to hang, but stars work | Well something is working... To get as far as screens able to tell you something is wrong, logically you need a working Z80 (verified), some working ROMs (verified), some working RAM (not verified), and approximately 4 chips (2 critical) which ferry the data between them. Waiting on some known good RAM. No longer owned. |
| Scramble (2) | Konami Scramble | No sound | First off, the amp was cracked in half. Replaced this but still no sound. Analysis of the sound section showed it was doing nothing - this initially turned out to be the CPU. Replaced Z80, and activity was seen across roms/rams/AY synth chips, but nothing was coming out. I'd already tested the rams by switching them for two new ones, but it appears one of the new must have been faulty - changing the rams again solved the problem. |
| Scramble (3) | Konami Scramble | No sound | Again as with Scramble (2) the amp was cracked in half, so I replaced it. This board had a missing Z80 and both AY synths, replaced these and still no sound, although there was now activity. Replaced the rams since the in-situ ones looked a bit old and corroded, no change. The new rams did at least give me a good enough pin contact on a logic probe to find the chip select pins were both high constantly. Traced this back to a MS53204 - labelled as '04' on the schematics, and you can use a 7404 or even a 74LS04 here without problems. Sound now working, but some parts go very quiet and crackle depending on which AY output channel is making them - which would seem to indicate some kind of op-amp failure. Replaced all op-amps, works fine. |
| Scramble (bootleg) | Konami Scramble | Boots to cross hatch and resets/hangs | Verified all ROMs were correct, checked address/etc lines and while some looked a little dirty essentially everything was working. Since I still don't have a Z80 Fluke pod, I started piggybacking the main SRAM chips, the one in 1K caused the game to crash and reset when piggybacked, so I replaced it - game started working. Note: I had two replacement 2114s which I thought were both good, but only one works in this board, it's likely something else is slightly wrong somewhere, which only manifests itself on RAM that isn't outputting a strong enough signal - maybe CPU socket is the real culprit. |
| Section Z | Capcom Z80 | Background graphics corruption | Corruption seemed to be linked to ROM SZ13, but it verified OK in reader. With the ROM removed, the graphics were clearly wrong, but the corruption part vanished. The ROM data lines are controlled by some 74LS194s (two per ROM pair), piggybacking the one in 4C made the problem change - replaced this to fix. |
| Shadow Dancer | Sega System 18 | Very dark washed out picture | Expected this to be a sync problem or a missing video ground, but in the end it wasn't. Checking all the drive transistors, they were reading very high, I still don't understand why that was the case - the actual problem was one of the two 74HC4066 analogue switches - perhaps it was leaking onto the inputs. Initially I thought it was the one closest to the PCB edge since touching the pins changed the screen problems, but actually it was the other one. Replaced both anyway, picture is perfect now. |
| Shadow Warriors (1) | Tecmo 68000 | Tile graphics mostly missing and/or corrupted | Sold as working 100% on ebay. Turned out to be a faulty rom on the romboard, took the one from (2) below, fixed. |
| Shadow Warriors (1) | Tecmo 68000 | Scenery sprites missing | Initially seen and assumed to be the problem above, this happened again, but flexing the board made them appear. Reflowed solder on the mini romboard, to no effect (shame, it was very tidy before). Noticed while flexing the board that they'd sort of appear again. Checked surface mount chip legs after a feeler test, 4th one down had a cracked solder join on one leg. |
| Shadow Warriors (1) | Tecmo 68000 | Most graphics and all text missing, replaced with empty character graphic blocks, only overlaid graphics visible. | ROM 5 on the video board appears to be a character ROM. The socket had corroded (strange as the rest of the board is clean), replaced socket and cleaned up the chip legs. |
| Shadow Warriors (2) | Tecmo 68000 | Sparkly jailbars | After buying (1) above, I pulled this out of my board rack - it used to work fine. Now has faulty mini romboard, sparkly jailbars are suspected to be character graphics for the text overlay - as it affects backgrounds and sprites equally - probably RAM. Gave to someone else to try fixing. |
| Shadow Warriors (3) | Tecmo 68000 | Sound dropping, occasional flashes of graphical corruption. | Sound was a bad volume pot, what a surprise. Graphics were either the extra romboard pins, or pins on various socketed RAM chips on the video board. These were all filthy so I cleaned them all up with very fine wet & dry paper and everything is fine now. |
| Shao-Lin's Road (1) | Konami 6809 | RAM1 ERROR | RAM1 is the pair of TMM2009-A SRAMs near the middle of the board, probing one showed the data lines were extremely weak/dead. Replaced this to fix. |
| Shao-Lin's Road (2) | Konami 6809 | Backgrounds were small sections of tiles stretched across the screen. | 74LS244 missing on the left, looked like a repair nobody bothered to finish. Put one in and it works perfectly. |
| Shao-Lin's Road (3) | Konami 6809 | RAM F10 BAD | TMM2009B-P in F10 bad, replaced to fix. |
| Shinobi | Sega System 16 | No sound, some corrupt sprites | I think this one has suicided, it's a later Shinobi that has a suicide Z40 on the sound. I'm getting an unencrypted sound rom made and the suspect graphics roms. Fixed graphics problems, removed suicide battery chip and put in decrypted rom - still no sound. Then, the board died entirely. Fuck. Parted. Update Got a spare E-SWAT board, so swapped the romboard from Shinobi onto it. Sure enough the game ran again with no sound, but I *had* applied the desuicide trick. That was when I noticed two other sound eproms were simply not there... ;-) |
| Shinobi (System 16A bootleg) | Sega System 16 | Some pixels of lines lagging on sprites | Rom 17 was bad, pretty easy fix really. |
| Shoot Out | Did nothing (no roms) | This came to me as an "untested" which appeared to mean "has no eproms at all". I burned a complete set and luckily it works! | |
| Side Arms (1) | Capcom Z80 | Alternate lines of sprites missing | Still working on this.. Initially I suspected ROMs but the alternate lines were alternate lines of the full sprite field, not each sprite. Problem appears to be the Line Buffer 2 circuit on bottom board - accesses to the TMM2014 in that circuit are far fewer than on buffer 1. Replaced the 2014, this hasn't helped. I've ordered full new components for this circuit, and will simply swap them out one at a time to try and resolve the problem. UPDATE: I bought a cheap Side Arms board which turned out to have a battered (and slightly sick) top board, so donated it's bottom board to create one totally dead set (parts) and one fully working. |
| Side Arms (bootleg) | Capcom Z80 | Half the music channels missing / VERY quiet. | Amusingly, ALL Side Arms bootlegs have this fault. Your board isn't faulty, it's just wrong. If you look at the schematics for Side Arms, they show two resistors coming in on pins 5 and 7 of the 16 pin op amp. The one on pin 5 is not implemented on real boards, but the bootleggers did. End result? A severe drop in power on one DAC output. Whoops. Snip this resistor off and your sound will be fine. |
| Silent Dragon | Taito ? | Graphics glitches, resets | On visualcheck found a damaged track on the underside of the PCB - patching this restored everything, also replaced various damaged filter caps. |
| Silkworm (1) | Tecmo Z80 | Specific sprites flickering after warmup | After trying all the various reseating tricks, I noticed that when warmed up, putting pressure on the tiny daughtercard on the lower board made the problem go away. I suspected a dry joint and basically reflowed every joint on the board riser. Still not fixed. Further examination putting pressure on chips with fingers located the problem as being the LS138 in E3 on the daughtercard. Unfortunately two of the solder pads came off the chip socket on the PCB, and the tracks they broke from had to be wire bridged, but it's ok now (finally). |
| Silkworm (2) | Tecmo Z80 | Crackly sound | I suspected caps or op-amps, but started tracing from the DAC. DAC output was clean. Op-amp output was clean. Amp output was clean! Poking around a bit with the probe I found that pin 4 of the YM3014B DAC generates a pop when touched with the probe. Closer examination showed the pins feeding this, on the YM sound chip, had no solder on them. Another fault since manufacture, fixed. |
| Silkworm (3) | Tecmo Z80 | Dead, sprite colour problems | The being dead thing was down to the resin daughtercard which had snapped off. Repaired this (tricky but possible) and the game booted and ran. Some sprites flicker different colours. Sprite ROMs are fine. Used a process of elimination by removing the socketed RAM to identify which was for sprites. Sprite RAM on this board family is a huge bank of 20x 4164s. I checked all the data output pins and found one of the 4164s had no output, despite all other signals looking good. Two other 4164s had no output, but also no input and strange looking signals, I suspect they're just not needed on this game. NOTE: You need the game running or several 4164s will be idle. Desoldered the definitely suspect 4164, put a socket in and refitted the chip with the data out leg lifted in case it was being pulled down by a fault elsewhere. Still bad, new RAM is on it's way. Update: 4564 RAM arrived, while the pinout is the same the timings are totally different - now getting a bar of sparklies specifically when the full screen blue tile sprites are drawn (start screen). I noticed the bar disappeared when a probe was placed on the CAS line for the bank of ram, so decided to try replacing the LS157 this traces back to (pin 9). New 74LS157 made no difference. Ordered 4164-12s to see if it makes the bar go away. Success! |
| Silkworm (4) | Tecmo Z80 | Sound sometimes drops out | This was sold to me with audio problems - initially it sounded fine, but when I put a little pressure on the sound section it jumped in volume, vanished, came back again and so on. I think the volume jumps were actually the pot, this was removed, exercised to clean, and resoldered. While i was doing this I noticed a resistor which had no solder... Soldered this properly, reflowed the amp 'just in case', and now the sound is stable. |
| Silkworm (5) | Tecmo Z80 | Unreliable booting, reset after 10-15 minutes. | Traced to dirty Z80 CPU socket and corroded CPU, replaced both and game stable again. |
| Silver Millennium | Jailbarred flickery text, scrolling line of bad background graphics every 8 pixels horizontally. | Flickery jailbars were down to bad solder from the factory on the RAM sockets - actually these sockets may have been post-factory, hard to say. Annoying to reflow as solder instantly bubbled, had to clear them out totally. Fault it was only supposed to have (horizontal line) actually scrolled with the background but the background ROM and RAM seemed fine. Fortunately Paradise actually marked their chip locations according to the part of the circuit - while checking over all the 'BG' chips I found a 74HC273 with an obviously stuck output. Replaced to fix. | |
| Sky Adventure | SNK Alpha 68000 | Sound effects gone | Visible damage here, the row-of-pins mounted resin covered audio chip was missing (later discovered in the bottom of the shipping box...) Repair for this is basically like Jaleco input board repairs - scrape off enough resin to reveal some pin metal and carefully solder that bastard back together. Works fine now. |
| Sky Kid | Namco Pacland | Sprites all black blocks | ROM 7 was physically broken, top half cracked off. Replaced this and got corrupt sprites - incorrect parts of sprites being used. Checked sprite ROMs, a couple of address lines were floating. Traced to faulty 74LS273 just to the right of ROM 7/8. |
| Solar Warrior | Background mis-tiled, sprites flickering according to frame | No brainer this one, half the pins on the bottom board of the rom sockets were bent over and touching eachother. Nice. This is why boards have legs, please note.. | |
| Son Son | Capcom Z80 | Sound fault (digital hiss) | Sound fault only appeared after playing for a minute, Eventually worked out that it started during certain sound combinations, noise being generated by the first channel on one of the AY-3-8910s (closest to the side of the board). Sound ROM/RAM verified OK, so replaced AY, sound fixed. |
| Soul Edge | Namco System 11 | Vertical graphic glitches, affecting 3D engine in a flickery kind of way | A seller had shipped this to me from the US in some bubblewrap and a plastic bag (seriously), and the board had developed some kind of flex/warm-up problem. After lots of testing and pressing on various chips on the top board, it was traced to a series of RAM chips. Reheating the surface mount legs on these (urgh) made the problem go away. |
| Space Fire Bird | Shot and enemy explosion sounds missing. | This is usually down to the 74LS05s in IC22 and IC23, but on this occasion they looked OK. The next common failure are the LM324 op-amps, and sure enough one of them had died (IC24 I think), replaced both to be on the safe side - sound restored. | |
| Space Fire Bird (bootleg) | Green missing from sprites, sync failed, sounds missing, stars intermittent, etc | Another ebay.de special sold as working but not. Intermittent stars was a RAM seating problem on video board. Green missing from sprites was one of the 3 colour caps (C3) having a broken joint. Sync problem traced to a mess of a semi-working transistor and a nasty big wire hack - pulled the crap off and put a new one in. Missing shooting effects were down to the capacitor that sits between the tone/duration pots on the sound board not being there. Various filter caps in the sound section were also wrong or missing. Two transistors in the sound section had been removed and bridged. Spent hours rebuilding this board according to the schematics and it works fine now. Last remaining issue is a red raster flash when your ship is destroyed. Should be full screen (allegedly) but isn't. Tagged this as fixed until I see another one to know if that's true. Verified normal. | |
| Space Gun | Taito Z System | V-PROG ROM ERROR, corrupt sound, sprites large blank rectangles, corrupt backgrounds. | V-PROG ROM ERROR turned out to be C57-22 EPROM, I wasted a lot of time thinking it would be the sub-CPU ROM and checking tracking. Corrupt backgrounds and missing sprites down to faulty mask roms C57-02 and C57-05, 27C800 and 27C400 replacements. Corrupt sound down to faulty mask ROM C57-07, another 27C400. Suspect this board had a short at some point for pin 10 to fail on all those mask ROMs - perhaps solenoid voltage shorting to common ground. |
| Splatterhouse (1) | Namco System 1 | EEPROM BAD | Initially suspected to be the ROMS, these checked out OK. The actual EEPROM on the CPU board also checked out fine. After checking with a known good CPU board, it was clearly a fault on the top (rom) board. Gut feeling swapped the 64A1 custom sound CPU with a known good one and the game worked fine. Returned this board to the owner as-is, 64A1 is nearly impossible to source. Update - repros now available for these parts. |
| Splatterhouse (2) | Namco System 1 | Alternate line corruption and flickering on sprites, corruption would clear as game warmed up but sprite colours would go bad. Some sound missing | Sound was simple - failed TL084 op-amp which is very common on these boards. Graphics were more difficult, on the CPU board I located the sprite RAM - this is a pair of 2018s in D6 and E6. Piggybacking E6 resulted in the corruption stopping and the sprite colours to stay wrong straight from boot. Replaced E6, problem not solved. The flickering/corruption became very rare, colours were always wrong. Removed RAM and tested at socket, some of the data lines which should have showed very minimal activity from attempted writes were dead or floating very low, particularly COL0 and COL3. Only chips common to those are a graphics custom, and a 74LS173 in D3. Piggybacked 173 and sprites looked perfect - replaced to fix. |
| Splatterhouse (2) | Namco System 1 | Sprites sometimes degrading in an interference pattern or disappearing | Went back to the sprite section as worked on previously, probing one of the data lines resulted in the problem starting to appear when it wasn't. Again controlled by a 74LS173, replaced and those data lines became stable, but problem still remained (less frequently). The sprite data lines are controlled by three 74LS173s, with two replaced I started shorting the pins on the third and found that it was possible for it to cause the remaining issues seen even though during tests it looked ok. Replaced it anyway, all problems gone. Interesting that every type of one chip was bad. |
| Squash (Gaelco) | No sound | The amp and volume pot were both physically damaged. The pot was a simple metal clip casing so I repaired it, but the amp is pending replacement. Replaced, all good. | |
| Strato Fighter | Tecmo 68000 | Strong green tint | The colour in this game is created by a bank of 3 PALs AAA16K4P-35, which then filter through a variety of flipflops and counters before reaching the resistors and caps at the edge connector. In this case I traced from the edge connector backwards, until I hit those PALs. If one fails, the colour it's dealing with will be stuck on - in this case green. The PALs are identical on this, Shadow Warriors (Ninja Gaiden), Tecmo Knight, World Cup 90 and possibly other Tecmo boards. Got a replacement from a Shadow Warriors, mostly fixed the issue but left a slight colour imbalance. Replaced all three with SW ones and it was fine. Also noticed sparklies on the backgrounds at the top of the screen - this came down to one incorrect RAM on the video board, -12 instead of -10. Switching sockets with one of the -10s was enough to clear the problem up. |
| Super Bubble 2003 | Limenko | Sparkles on sprites | These boards have at least some chips running at 3.3v and there is a regulator circuit for dropping 5v down to this level. Some boards have a potentiometer, slight adjustment of this will bring the circuit back in spec. On boards without an adjustment Monstermug confirmed that replacing caps C49 and C178 can clear it up. Be very careful when disassembling this game as it is very easy to break the volume control. |
| Super Marukin-Ban | mitchell | White screen, sprite layer corruption | White screen due to pre-CPS suicide - revived with new battery and Kabuki reprogrammer. This revived the game but sprite layer was corrupt. ROMs and all RAM checked out fine, suspect 86S105 custom. Replaced custom with surface mount socket and a part from a Black Dragon video board, game repaired. |
| Super Pang | Capcom Mitchell | Boot to dark green screen | Applied suicide fixed as per Dead Battery Society page and it was just fine :) Unfortunately this forced a re-regioning to World revision instead of Japanes, but it's better than dead. Read the instructions on that page carefully as it's a little more involved than CPS1 fixes, also take note of the NVRAM clear. |
| Super Pang (2) | Capcom Mitchell | Incorrect colours on desuicided board. | Previously desuicided, but someone had broken the raised pin on the ROM in 14h clean off. Burned new rom, reattached the wire, done. |
| Super Pinball Action | Tecmo 68000 | Horizontal rasters on/off plus high pitched squealing sound | On the right side of the top board, half way down is a 47uf 16v capacitor used as part of the 68k reset circuit - this was bent over with one leg pulled out. Replaced to fix. |
| Super Ranger | Suna Z80 | Dead sound, amp burning up | 12v supply cap for the amp had broken free due to cracked solder. The cap seemed reasonably OK on an ESR meter given its age so I just refitted it. Replaced amp with one from a broken choplifter bootleg, all fixed. |
| Super Zaxxon | Sega Zaxxon | Blue missing, sounds crackle after a few minutes running | Tested and working. SO WHERE WAS THE BLOODY VIDEO BLUE PIN? Repaired the missing edge connector pin and blue is back. The sounds are the same problem as Future Spy, fixed, see above. |
| Swing Gal | No sound | LM324 op-amp had failed, piggyback with working chip was enough to prove the fault. | |
| Taisen Hot Gimmick 4 Ever | Psikyo PS4 v3 | Interference bands on lower half of screen, rumbling behind audio. | Doing a 'finger test' on the surface mount chips to see if any of them appeared to affect the screen, I found one of the 62003AF chips used to drive the inputs was extremely hot despite inputs working correctly. Replaced this and all faults resolved. These are 7x transistor chips, it seems likely one was internally shorted. |
| Tatsujin | Taito Toaplan | Diagonal interference, no boot | Similar to the problem with Flying Shark boards, replace cap C16 which is causing the power-on reset to fail. |
| Teenage Mutant Ninja Turtles (1) | Konami TMNT | Sound distorted while any samples are playing | Resoldered cap joint/etc - seems to have made no difference. Maybe this is related to one of the op-amps, or maybe this uses a two channel amp which gets upset if both try to play? Update it's better, but still not fixed... I resoldered lot's of audio components - but I suspect one of the op-amps has bit the dust when warmed up (C324C 16 pin). Update replaced the one I thought was at fault, but it hasn't changed matters. Pretty sure this *is* actually a cap issue after all.. Lost track of replacements, will do the whole lot. Update After replacing various sound section parts, I can only conclude there is some internal PCB damage on this board. It is parts now. |
| Teenage Mutant Ninja Turtles (2) | Konami TMNT | Not running | The left most small blue crystal (from edge connector point of view) had a leg ripped off. Repaired this, board runs fine now. |
| Teenage Mutant Ninja Turtles (3) | Konami TMNT | Graphics corrupt, doubled sprites | Started by checking the SMT chips, no problems there, next started looking at the sprite ROMs. Noticed with the finger test that all four had a slight effect on the picture. Checked more closely, and pin 3 of all four sprite ROMs was stuck low. Traced this to a 74F151AN in G6 with stuck outputs. Replaced with 74F151APC to fix. |
| Teenage Mutant Ninja Turtles (4) | Konami TMNT | Corrupt screen, RAM/ROM errors on boot. Rumbling/popping noise in sound. | Checking address lines on affected code ROM revealed address line 4 was dead, this was traced to a damaged track under the socket of J17. Repaired this and the game booted and ran with intermittent reporting of G27 RAM being bad. While it seemed unlikely after a piggyback test, replacing G27 resolved the fault. Sound fault due to 1000uf/16v 12v filter capacitor. |
| Tenchi Wo Kurau II | Capcom CPS1 Q-Sound | Dead | This is a CPS1 + Qsound board, which have two suicide batteries. Taking the case off and checking, the Qsound battery was dead. Applied the Qsound fix detailed at the Dead Battery Society page (http://www.arcadecollecting.com/dead/dead.html) and this revived the game. I also took the hacked rom to remove suicide from the romboard, and applied the changes made between US hacked and US original to the Japanese rom. Along with the romboard fix also detailed on the site, the Japanese version rom 23 is here: http://www.system11.org/temp/ROMs/tk2j23c_x.zip |
| Terra Force | RAM NG | Faulty RAM replaced at E7, located via piggyback tests. It seems common for the Toshiba RAM on these boards to fail. | |
| Tetris (Sega 16A) | Sega System 16 | Dead | Expected it to be suicide but it wasn't. Note: these older 16A boards use LOADS of power, make sure your loom and adapter are fully wired or things will get pretty warm. I had two of these, so I cheated and swapped the video boards, reseated all the cables, and it works! |
| The Lady Hunter | Nichibutsu 8991 | Slight red bleed | 74LS74 in 5N is not sufficient for these boards, replace with a 74S74 to resolve right side bleed / sparke effect problems. |
| The Lady Hunter | Nichibutsu 8991 | Corruption overlaid on some graphics, many graphics missing. | Noticed corruption over characters is removed by pulling ROM 9 but suspect the problem is actually in the layer used by this chip. Unsure how this happened but problem turned out to be 10+ of the 27512 ROMs all being bad! Potentially caused by static but at a loss really. |
| The Last Day | Dooyong | Jailbars on some background graphics, most obvious in stage 2 | Easy fix - poorly soldered from the factory at the ROM sockets - a couple of pins were just floating in air, probably broke free from a very slight fixing in transit at some point. |
| The Punisher (1) | Capcom CPS1 Q-Sound | Dead | Q-Sound suicide as detailed on the Dead Battery Society pages - easy fix. Later I also applied the C board fix while doing another one as I'd dismantled it for testing. |
| The Punisher (2) | Capcom CPS1 Q-Sound | Dead, poor picture. | Q-Sound had been desuicided by a previous owner, but not properly! R33 and the capacitor nearby were both still intact, they'd even switched the Kabuki for a Z80 but you still need to make those changes. Did them and the C board fix and it came back to life but the picture was faded due to poor contact on the edge connector. Used metal polish and then alcohol on this and it's fine now. UPDATE: the fan was way too noisy - had to modify a standard box fan to fit, and ended up replacing the double sided edge connector from the front by carefully cutting one from a brand new fingerboard - speaker noise GREATLY reduced and no more burned pins. |
| Thunderblade (1) | No boot | Suicided - decrypted ROMs are available, simple replace EPR-405/406 and put a 12mhz or better 68000 in place of the encrypted CPU block. I'd recommend better if you can find one, these do run slightly overclocked. | |
| Thunderblade (2) | Whistling/buzzing sound behind audio | Sound changed if I placed my finger near the analogue switches in the sound section, especially the 101 ceramic caps. Recapped the entire PCB in the end, problem very likely the three 10uf/25v ones near the sound connector. | |
| Time Soldiers | SNK Alpha 68000 | Every other pixel of every second line incorrect colour on some graphics | Done a lot of investigation on this - there's a back of 8x 6116 ram, I've noticed that the effect gets worse if a certain data line on any one of four of them is probed. These all trace back to a LS153 but it looks OK even when piggybacked. Not going any further with this until I build a small adapter to read the 23C1000 28 pin mask roms. Update: parts board now. |
| Top Gunner (1) | Konami Double Dribble | Display faded, colours bleeding | I'd seen this before on a Bosconian board, and it can sometimes be indicative of a bad video ground pin on cabs where vid gnd on the monitor is not already connected to common ground of the loom, relying on the board to supply this. Sure enough, vid gnd track near the JAMMA connector was broken. |
| Top Gunner (1+2) | Konami Double Dribble | Booted up with 'bad color ram' error and the board location of the big Konami resin block | On closer inspection, resin block had a broken pin. Fixed this, board back to life, easy! (now done two of these with identical faults!) |
| Top Gunner (2) | Konami Double Dribble | Corrupt sound (initial) | I've noticed this corrupts the sound until the jeep has crashed once and played a particular sample. I suspect some kind of reset signal on bootup is not happening. Board has had some work in the past near the sound section. UPDATE: gave this to a mate as a freebie, it won't get fixed. |
| TourVision motherboard (1) | Blue missing | Near the memory clear button on the PCB are 8 transistors, these are the video amp - T8 had failed. It's easy to check these with a scope. Replace all colour ones at once to avoid output balance problems. | |
| TourVision motherboard (1) | Sound very quiet | TourVision has an audio mute circuit which cuts audio when no coins are inserted - it's not great using a TTL output to pull the amp input low and as such just sounds very quiet when muted. This PCB was stuck on mute due to failed 74LS125 in IC14. | |
| TourVision motherboard (2) | Green missing | As above, Phillips C547A transistors seem to give an excellent output compared with the ones normally fitted. | |
| Tricky Doc | Unreliable sync, incorrect blanking, sparkly logo (sprites) | Unreliable sync went away by magic while looking at the board, unable to replicate fault. Blanking was faulty causing blocks of game graphic to be drawn in a glitchy flickering fashion off to the left. Noticed this got better as the game warmed up, with freeze spray isolated a board area and while checking chips with a probe, found a 74LS20 in F3 which would immediately cause the problem when probed. Replaced this and blanking started to work correctly - also noticed this chip is part of the critical path for screen sync, so it was likely the culprit of that fault too. Removed a few sprite ROMs to force solid blocks to be drawn, this showed a pattern of black dots in the sprite RAM. Piggybacking the 2148 in G4 made the dots go away, replaced chip - sparkles gone. | |
| Twin Cobra (bootleg) | Sound corrupted, mostly a series of odd pitches sort of in time to the sound effects | Easy fix - one of the pins of the YM3812 was loose due to lack of solder. | |
| Twinkle | Player 1 start + button 1 stuck | Inputs go through some 74LS245s by the edge connector, two of these chips were faulty. | |
| Twins | Unreliable boot | Capacitor C24 loose, part of reset circuit. | |
| Undercover Cops | Irem M92 | Sound problems (weak, channels missing) - corrosion damage | Sold at working, arrived with the sound section looking like it had an acid bath. The cause of this was capacitor leakage from at least 4 or 5 capacitors including the larger ones. Some had eaten through tracks at the sound custom, some had destroyed resistors and so on. A simple if difficult fix, I had to replace all the affected sound components, and rebuild the 9 damaged tracks with strands of wire. WARNING: seems to be a common problem with M92 games with the brown capacitors fitted, I'm not aware of this problem happening to the ones fitted with green caps. If you see even one of them start to leak, replace all of the same make. |
| Up 'N Down (2) | Sega System 1 | Sort of rasterised sprite corruption generated by some sprite frames and not others. Weak sound effects. | I think this is probably a sprite ROM or RAM problem, not diagnosed it as yet. It was sold to me as working (as usual). Diagnosed as a sprite ram fault. The Midway board version has 4x 2148 RAMs near the two sprite ROMs. Changing the positions of them changed the broken sprites, so each was swapped out until the broken one found (last one of course..). Still getting slight sparkly trailing edges on sprites when moving - this is because the new 2148 isn't fast enough, so it'll be replaced as soon as. Update:Playing this recently showed the sound effects were weaker than they should be. A quick visual check showed the polyester capacitor closest to the amp had a corroded and broken leg, replaced to fix. |
| Up 'N Down (3) | Sega System 1 | Jailbars over the whole screen, sprites corrupting, colours fading, tile corruption | This was actually a parts board I decided to try to fix. Jailbars turned out to be a broken track from one of the 2148 RAMs to the CPU in the bottom right corner. Sprite corruption was a failed TMM2009 near the sprite ROMs. At this point the tile corruption started on the logo - I was unable to diagnose that fault before the colour section started to drop out. Designated parts board now. |
| Up'N Down (1) | Sega System 1 | During running, screen froze. Game only gave a black screen after this. | Pin 6 of the custom Sega Z40 (the clock pin) was stuck high. Tracing this back through IC142 (74LS04 inverter) to IC141 (74LS161 counter) showed one of the counter inputs (pin 10, ENT) was neither high nor low, jamming the counter. Tracing pin 10 up the board to IC44 pin 6 (74LS107 flip-flop) showed the flipflop was jammed. Lifted pin 6 and the problem remained (not high or low) but the game started running again (wrongly). Replaced the 107 and board runs fine. |
| USAAF Mustang | Incorrect colours (blue tint everywhere), some sound missing | Someone had tried to fix this in the past with a heatgun method - this had caused various legs on SMT chips to detach, including a couple on one of the OKI chips. Soldered them back down - sound correct. For the colour problem I started looking at the actual colour output, levels were correct but the signal looked 'wrong' for blue. Piggybacked each of the colour RAMs (UMD6116K-2), the second one resulted in radical changes. Replaced RAM - colours now correct except sometimes areas of screen would change colour. The fault behaved different with different 6116s, checked it with the worst of them in and found one of the address lines looked ok, but the problem stabilised when one of them was probed. Replaced controlling LS157 and fault resolved. | |
| USAAF Mustang | Incorrect/missing colours or graphical detail in background tile layer | Traced to a bad pin on SMT chip IC132. | |
| USAAF Mustang (2) | Some missing sound and parts of music. | Previous owner had reflowed and replaced various components at random including replacing some caps with incorrect values. None of these things were the problem. The first OKI was making no sound at all, and when I looked at the attached sound ROM the data lines were barely glimmering. Found that the 5v pin to the ROM was a bad joint, reflowed and sounds were restored, but incorrect as if fading in. Removed ROM to verify contents, then replaced OKI. New OKI sounded even worse, replaced again - this one had a dead address line. Unfortunately the repeated removal and fitting of SMT chips damaged one of the solder pads requiring a jumper wire. Discarded box of 'new' OKI chips and reclaimed one from a Bad Dudes which was known good until the video board failed. Sounds now correct, also replaced all the incorrect caps and cleaned up the previous repairs. | |
| Valkyrie no Densetsu | Namco System 2 | Black screen, or resetting when attract starts. Test mode crashes and resets continually. EEPINI EEPBRK displayed every boot, will not coin up. | Occasional black screen caused by failed solder on SMT chip next to the main CPU. When trying to enter test only part of the screen was displayed, with FF at the start of any items displayed briefly until crash. Remaining problem was due to the settings EEPROM, the contents must have been badly corrupted during one of the black screen resets when test mode was being attempted. I piggybacked the chip on the working donor board and saved settings on there, causing both chips to write. These could also be erased by a ROM programmer for instance. |
| Valtric | No sprites, colour balance problem on certain colours, picture dark | 82S129 in position 1S top board was missing - this is sprite priorities. Colour balance problem traced to 74LS174 next to three SIL customs on the lower board. Additionally refitted the lowest one of these (for red) as it was poorly fitted. | |
| Vandyke | BAD BACK RAM | The RAM error message on these games is quite useful and prints the incorrect byte it received. Piggybacking various RAM banks identified that the BACK RAM is a pair of xx64 in positions xx and xx. Piggybacking a known good chip over either of these however resulted in a different failure checksum. | |
| Vanguard | Dead | The simple things are often the best ones to check first. The crystal was dead as a dodo :-) Finding the 11.289mhz crystal proved impossible, but 11.2896 is a common one used in radio equipment - someone mailed me a couple :-) | |
| Vapor Trail | Data East MC68000 | Dead, green screen + reset, corrupt text, corrupt backgrounds. | This board was a mess, looks like it had been wrapped in spiderweb and wet paper. Started by probing various bits of RAM near the CPU ROMs, found one where the pulses would change and flicker when it was touched in position K7 on the mainboard. Replaced this, board booted to a screen of green bars and started resetting. Checked more RAM in the CPU area, found a suspect one in F5, replaced this and the game booted! Background graphics were jailbarred and flickering, text flickering and corrupt. The ROMs are all talked to via 74LS373s, touching one in the romboard corner made the text corruption change. Further checking found that the track between one of the 373 inputs and the CN1 interboard connector was broken. Wire jumper fixed the text. Background graphics changed when another 373 in D17 was touched. After much tracing of the inputs and outputs, two more broken tracks from pins 7 and 14 were located between some unpopulated ROM sockets which form the track path. All fixed :) Happy about this one as I like the game and had written this PCB off as dead. |
| Vasara | Seta SSV | Lost sync, blocks of colour only | I could hear the game running when coined up, so immediately suspected possible SMT join failures. Sure enough, under a large heatsink lives the main SETA graphics CPU. Lots of high density pins, several of which had broken joints. Took a long time to fix, but it works now (suspected damaged due to inadequate packaging). |
| Vasara (2) | Seta SSV | Dark washed out picture | Colour output transistors (C1674) near the edge connector had all failed - replaced to restore correct brightness and colour. Sync had failed too, but did not cause a problem - replaced anyway. |
| Vasara 2 | Seta SSV | Dim picture, blue tint | Red and green colour output transistors (C1674) near the edge connector had failed. Replaced all four to restore picture. |
| Vasara 2 | Seta SSV | Scrambled graphics on title screen and in game | Another common fault on these, found two loose pins on the SMT under the large heatsink on the top board. |
| Vendetta | Konami X-Men | Half of the control inputs failed | This arrived "working", but obviously hadn't been tested properly. All the left/rights and all the credit buttons were dead. Tracing the control inputs, all the problem controls came down to two 74LS253s in 9A and 11A. These encode the control inputs and send them to a Konami custom chip. Oddly, they appeared to be outputting correctly, but probing the output pin on either made the inputs go berzerk. Suspect internal damage to the chips had occurred, replaced both, board now fine. |
| Violent Storm | Konami X-Men | Garbage on boot, graphical errors, resetting | Garbage on boot I got lucky with - checking some chips near the code ROMs, I found one with traces but no signals. Traced this back to the PAL near the code ROMs. Traced all the tracks further and found it should have been connected to one of the ROM pins, but wasn't due to a hairline crack under the ROMs. There should be no dead connections on that PAL for reference. After repairing that I was left with graphical problems - bits of sprite and background being missing - this came down to several cracked solder joins on the custom 7K. Game now looked fine but kept resetting, noticed flexing near the ROMs would trigger this, eventually isolated to faulty ROM sockets. |
| Volfied | Dead (physical damage) | Taito love their nasty resin covered daughtercards. They especially love using very thin, fragile pins to hold them on, and this one snapped off. Use a stanley knife/craft knife to cut away some resin covering and expose a bit more leg. Clean all the solder holes out, then fill with solder one at each end. Carefully hold daughtercard in place and melt the solder in the end holes to anchor it. Fill remaining holes. This is how to replace resin card parts the legs have snapped off from. | |
| Vulcan Venture | Konami Twin 16 | Missing backgrounds, corrupt gfx | The missing backgrounds were easy to sort - one of the roms had the GND leg hanging out of the socket. This left me with the corruption issue. Test mode reported "P18" bad, which is F18 in reality. Most VV boards are 3 layer types, the smallest board having 32 character roms on it. The problem is, the sets in mame are all with 4mb mask rom images from the 2 board version, F15->F18. On the split rom version, F15 reports as F16, F16 as F17, F17 as F15. and F18 as F18. Yeah, thanks Konami. There are 8x 27512s for each of the 4mb rom images, labelled with the F number, and A->H. To get the right segment out of the 4mb image you must treat them as 4 sets of 16bit split pairs. A = set 1 lower bit range, B = set 1 higher bit range, and so on. The only exception to this was F18 for some reason, which has the two middle sets switched. None of the others do. Thanks again, Konami. After spending some time working this out, all the ROMs checked out as being OK. Testing the sockets of that bank showed part of the F18 bank had a broken address line track. Repaired it, corruption gone. |
| Vulgus | Capcom Z80 | Garbled background gfx, no sound, faulty inputs | Doesn't even make a 'pip' from the speaker on boot. Amp was quietly cooking itself and was replaced with a new one, which fixed the sound. Garbled tiles were down to a faulty ribbon cable connect between the boards. Inputs (coin and p1 up stuck) came down to two 74LS367s which sit next to the edge connector, which had shorted the relevant pins to ground. All fixed now! |
| Wakakusa Monogatari Mahjong | Allumer MJ | Some button inputs unreliable | Enough of test mode was usable to find buttons on COM3 were being read unreliably and sometimes as COM4 equivalents. Common Mahjong fault, matrix column driver chip failed - TD62003AP in U30. |
| Wardner (1) | Taito Toaplan | CRAM ERROR | Initially reported CRAM ERROR, then by the time I got it upstairs to the repair bench, it turned into total death. With the code ROM in place, the board would just hang on boot, with it removed various parts would come to life and start resetting. I started checking the CPU RAM address lines, and found address A8 was dead on one of the RAMs - a track must have been either cracked or about to, under the RAM. Wire jumper has fixed this, back to CRAM ERROR. I started checking the RAM I suspected to be for colour (had a good idea after diagnosing a Flying Shark), and found a pair of RAMs, one of which has nearly all dead IO lines, while the one next to it looks healthy. Piggybacked a good 6116 with the data legs lifted, and sure enough they pulsed away. Either the RAM installed is dead or something is holding the lines down, I'll have to snip a leg to find out. |
| Wardner (2) | Taito Toaplan | I/O ERROR, no sprites | I/O ERROR can happen when coin inputs are jammed. Checking on the JAMMA connector, coin 1 was stuck low but the supporting resistors/etc all looked good. Replaced 74LS240 in N20 which fixed this. Missing sprites were very obvious - all the sprite RAM was physically broken. Replaced all 6 and sprites came back to life. |
| Whizz | Characters all over the screen, no sound. | Character RAM at S4 had failed, replaced this and game looked fine. Sound due to damaged volume control. | |
| Wonder Boy | Sega System 1 | No sound (tone) | The sound CPU looked absolutely dead. Swapping it for a good one resulted in the same sound, but at least the address lines started pulsing. Checked the sound EPROM (matched the one in the System 2 set) and found it could not be read. Replaced to fix. |
| Wonder Boy In Monster Land | Sega System 1 | Dead | Caused by suicide battery - the only fix for these is to replace the Z80 with a normal one, and replace the 3 code ROMs with decrypted ones. |
| World Cup '90 (bootleg) | Title screen graphics missing, pitch drawn incorrectly. | This is a board flex issue - it works fine when it's warmed up, but I haven't found the problem despite many hours of reflowing and checking. Going to give it one last check when I have some freeze spray, after that it's joining the parts pile. Now used for parts. | |
| WWF Superstars | No sound | Volume control physically broken, many caps with pulled legs too. | |
| WWF Wrestlefest | Everything turned Cyan and Yellow! | I traced this by nonscientifically poking around, to a pair of very badly replaced and socketed rams (IC19/IC20, top board). I refitted these and made the hack a little more robust - and it works now. | |
| Xexex (1) | Konami Xexex | High pitched tone over sound on left channel | Konami 054544 customs are well known for leaking caps and resulting damage. I replaced the caps finding no damage, so they were probably OK. Next I replaced the op-amp underneath the 054544 (difficult job), I *think* this made things better. Tried another 054544 and no change. At the same time I replaced the surrounding filter caps and while the issue is still there, it's greatly reduced and usable now. Have now seen this problem on three boards, suspect it to be very common - two were untouched and looked visually fine. |
| Xexex (2) | Konami Xexex | Visible cap leakage on sound custom, right channel very quiet | Another 054544 custom problem, one of the amp output caps had spilled electrolyte everywhere - cleaned it up and used a masking pen to cover the exposed copper tracks back up. Replaced bad cap, right channel still half dead. Replaced the amp input caps (the 4 closest to the Konami logo on the custom) and sound levels were restored. Replaced the rest just in case. |
| X-Multiply | Irem M72 | Small amounts of background corruption | This was sold to me as perfectly working - it was a shame to find out it was a conversion kit type, but more of a shame to see blocks of score readout appear in very specific places throughout the game. The tile engine is on the bottom PCB, so I switched this with the one from Air Duel (known working) and the problem went away. I then tried this with another known working baseboard, and it failed again. For some reason, this mainboard (an ex Ninja Spirit) only likes one baseboard (also from a Ninja Spirit). Why this should be is anyones guess - it makes no sense since all three work and are identical except for make and speed of RAM. Air Duel is happy with all three of the bases... |
| Xtom 3D | Hideous noise from board cage, freezing | Xtom 3D is a PC in a box. buried under the layers of ISA expansion cards, is a Voodoo Banshee graphics chip. DO NOT let this fan expire completely. Renewed all fans, noise gone. | |
| Zaxxon | Sega Zaxxon | Characters only being drawn on left side of screen, overlayed - right side is a mess of characters through which the rest of the graphics can be seen. Sounds play randomly if at all. | Wobbling the left side ribbon made the problem change - when I did this the characters started being repeated like two crushed duplicates instead of one crushed+corruption - this is very likely something to do with a stuck or floating address line which is carried by this ribbon. Ribbon itself seems fine. Shelved due to sound problem not being the normal caps issue. |
| Zero Team | Seibu | Some tiles on backgrounds flickering or not appearing at all. | Noticed that the problem would go away when touching one pin of the surface mounted quad in XX, traced this to 74LS373N in XX. After a piggyback test I replaced the chip and ended up in exactly the same position. On the 373 worked out what while several input lines affected the tile positively or negatively, one output line always fixed it while others made no difference. Soldered a 220pf cap across ground and that output after wasting a lot of time. Something is borderline and it's probably a custom part. |