Recently I've been sent an original Konami PCB for repair.The board was not in mint condition, it was heavily reworked, a lot of ICs (RAMs, ROMs, TTLs) were socketed and replaced.
Board was marked as working but with missing sprites, that was indeed what I got when I powered it up :
I entered in TEST MODE and performed a MASK ROM check which reported all the sprites devices as not good :
Object are handled by two custom ASICs (in QFP120 package) that work as pair, the '053246A' (which generates the addresses to the MASK ROMs) and the '053247A' (which draws the sprites) :
Looking at schematics made by 'jotego' from MiSTer (thanks to him!) I checked the connections between these custom ICs and the rest of the board, everything was correct.But when I went to probe the '053247A' I found some stuck outputs :
These are the color and priority bits sent to the '053251' (the priority control custom IC) :
The '053247A' was most likely faulty so I decided to replace it, luckily I had a donor board to take the part from.
Desodered the defective part with hot air :
The sprites came back :
Another successful repair.
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