Cps1 A board no video, coin op sound only.

[ovalfastlx]

I have an A board with street fighter 2 hyper, the B and C work, I tested on another A board.

The A board only has the coin op sound when they coin switch is triggered. no other sound or music. I only get a flickering white and sometimes purple screen that stays on the top on monitor.

checked cpu reset, Halt, clock and everything checked fine. I have a logic probe. I have run of things to check maybe someone has suggestions?

I know the custom chips go bad on these board. Trying to identify that issue and rule it out.

Thanks guys and gals, I'll post up pics later if that helps.

 

[NoAffinity]

Basic troubleshooting steps:
1) Check for power at all chips
2) Confirm no floating lines anywhere (need a known good board to compare against)

If all that checks out, then the only thing left is to swap the CPS-A-01 for a known working A-01. Dead CPS-2 A boards are a good source for CPS-A-01 replacements.

 

[Stoog]

Bad ASIC

Had this a few times in the past sadly unfixable unless you have a known good one off a damage cps1/2 A board that you could swap with