I recently ended up buying a Jaleco Lord Of King (Astyanax) PCB, which also came with a P-47 ROM board – or maybe it was the other way around. When I looked at it and my existing P-47, and the other Japanese P-47 type I realised that the sets in MAME are very likely incorrect.
As I went to dump this one, I came across the HN62312 chips. These are 2mbit MASK ROMs which follow a completely alien pinout to other devices, in fact it took a while to find pinouts at all.
Well I’ve designed an adapter, the first version is pictured below – I made a mistake and a ZIF socket won’t fit so the design linked to (which I’m having some of made now) has now been updated. It should also work for the 4mbit variants but I don’t actually have one to test with.
You can buy these from OSH Park now, all you need are pin strips and optionally a ZIF socket:
HN62312 / HN62304 adapter at OSH Park
Update: here’s the new variant.