CPS2 graphic issues

[pzlate]

I have a suicided b-board running decrypted roms that has graphic issues. I really don't know if it's the connection to my a-board or what. I've had it run perfect for short periods of times, but the sprites would slowly start corrupting over time. I left it overnight, booted it and it was fine for like a good minute but then started to corrupt again.

It just looks like sprites are being misplaced, I'm hoping someone more experienced in CPS2 can point me in the right direction.

E: I actually captured a video of the graphic glitches going away/forming again without touching the board at all.

My A-board seems to be fine, it runs my Alpha 2 board flawlessly.

Even Raz's suicide test has graphic issues with the text

 

[Blackfish]

Re-seat the boards, check for bent pins in the connectors. I've had a similar issue caused by 1 pin being bent in the connectors between the A and B boards.

 

[pzlate]

None of my pins are bent on the a board, and other boards work fine.

I actually must have slipped and shorted something when logic probing my b board because I just get a light blue screen when I plug it in now, caps already discharged. Gonna have to put this board back in the repair pile and hope I didn't kill one of the customs.

 

[dlfrsilver]

Hi, i bought lately an alien vs predator B Board that showed the cyan blue screen you got on startup.

Solution : check/dump the game maskroms. You will mostly discover some of them are flaky or shot.

I discovered on my own board that 4 maskroms were fucked up big time :/ Had to replace them by 27C160-100ns eproms.

 

[pzlate]

These same exact roms worked fine in another board, so in this case it was something wrong with the b board pcb itself.

 

[xodaraP]

Most times this happens it's because someone has used the wrong type of ROMs.

 

[fluxcore]

I also have a cps2 b-board which produces a light cyan screen regardless of the ROMs plugged into it. I presume either a custom or some 74s are bung, but haven't put any effort into troubleshooting. Definitely isn't a suicide issue, and discharging every cap on the board had no effect.

 

[dlfrsilver]

Check the maskroms. That's what i discovered on my AVSP. 4 fucking Maskroms shot

 

[Apocalypse]

I also have a cps2 b-board which produces a light cyan screen regardless of the ROMs plugged into it. I presume either a custom or some 74s are bung, but haven't put any effort into troubleshooting. Definitely isn't a suicide issue, and discharging every cap on the board had no effect.

I had this before too:
- one was a faulty LS245 located on one side of the B-board and connected directly to the program ROMs data bus.
- second was a faulty BGS PAL chip (one of its outputs is connected to the /OE signal of the 245s)