CPS1 MERCS freezing

[Rocco]

I bought this game some months ago , but the lack of TATE cabinet didn't let me play it ...

Game starts normally , credit OK but if I touch TEST or any action buttons , the game gets freeze.


What could be the problem?

I tried 2 CPS Base boards ,same result .
And those base boards works perfect with other games ...

[Asayuki]

The issue is on the B board, where the code EPROMs are. Try carefully reseating them as a first thing. Be warned that the C board has a suicide battery. You don't want to fiddle with it.

[Rocco]

The issue is on the B board, where the code EPROMs are. Try carefully reseating them as a first thing. Be warned that the C board has a suicide battery. You don't want to fiddle with it.

Do you mean pressing stronger eprom to socket with my fingers ?


Thanks for your help

[nem]

Reseating means pulling them off and putting them back in.

Is there a chance of it suiciding if the program roms are removed?

[Asayuki]

Is there a chance of it suiciding if the program roms are removed?

AFAIK the battery is only connected to the big QFP chip on the bottom of the C board. Hands off that thing.
However, Leonard is the real CPS expert; please correct me if I'm wrong, pal.

[Rocco]

The issue is on the B board, where the code EPROMs are. Try carefully reseating them as a first thing. Be warned that the C board has a suicide battery. You don't want to fiddle with it.

Thanks for the hint , do I need to take off the bigger EPROMs and re-install all again ?

[Asayuki]

Yes,
see this page, line 5527:
https://git.redump.net/mame/tree/src/ma ... s/cps1.cpp
The names of the files will make you understand which are the ROMs to unplug and replug. Be careful not to bend any pin.

[Asure]

Mercs has no battery on the C board. You want to check 11F, 12F 11H and 12H eproms. They are in a cluster of 4 in the corner below the C board.