Ive been chasing down an issue with a Data East TMNT with rev 3 cpu board.
I have both a Data East test eprom from marco and a system 11 test eprom from Leon Borre.
Neither worked, I resocketed the game roms (5B, 5C) Ram (5D) and the cpu (3D). And a few other chips. But after replacing the buffer 74LS274 (5C) Leons System 11 test booted. The PIA and control led flashes and the 5v is solid. All PIA outputs are correct.
When I put the Data East test in the cpu is locked up 5V and PIA stay lit. When I put the game roms they stay lit as well.
When I go thru with Leons Data East guide all signals are correct.
I read that you can use the system 11 test in data east cpu. But why would the system 11 test work but the data east and game roms will not?
Any suggestions are appreciated. I will respond asap if you need more information.