Strider CPS1 with corrupted graphics

[pdp80]

Hello, I'm new here and was brought here by channelmaniac's repair logs. I recently got a Strider board that has graphical issues.  There are vertical bars running through the screen:



I pulled the boards apart and re-seated them, also pushed down on all socketed chips to make sure they were seated.  Made no difference.  Has anyone seen this issue with a CPS-1 game?

Thanks!

[channelmaniac]

Common... Has many causes. Could be an issue with the board interconnects, an issue with the C board, bad RAM or frame buffer chip on the A board.

You need another A board to swap it out with to see if that's the problem. Luckily there are MANY MANY MANY cheezy Street Fighter versions in the CPS1 world. Just get one of those cheap and use it for parts.

[pdp80]

Thanks for the info!  I don't have access to another CPS-1 mainboard, but now I have an excuse to buy another game.     Once I get one I'll try swapping.

I pulled every socketed chip on the B-board I could find and cleaned the contacts and reseated them. Made no improvements (thankfully I didn't make it worse!) but I had fun powering it on with missing gfx roms and seeing what it looked like.  I'm a n00b when it comes to repairs, but this is a good motivator since Strider is one of my all time favorite games.

I'll check the board interconnects with my voltmeter while I track down another CPS-1 game.

Thanks!

[pdp80]

Got my SF2 board today and did some swapping around.

I swapped the A-Board, no change, still vertical lines.  I swapped the C-Board, which from the SF2 was a CPS-B-21 so it should be compatible, and still no change, still vertical lines. 
SF2 runs fine on the Strider A-board, so that rules out the A-Board.

This narrows it down to a B-Board problem. Is it most likely a ROM problem?  I've looked over the board thoroughly and can't spot any cut traces or bent pins that could cause a short.  I'm guessing it could also be a problem with the connections in and out of the B board.  Is there an easy way to check that?  Going pin by pin with my multimeter would take quite a while.

If it was a ROM issue, does anyone know where I could get another set?  I don't have an EEPROM programmer...

[channelmaniac]

Take the MASK ROMs out 1 at a time and look for bent pins, corrosion on the pins (inside surface and outer surface), etc... And for corrosion or damage to the sockets they are in.

[pdp80]

I pulled the graphics mask roms out one by one, cleaning the contacts and checking the sockets, powering the game on with each one missing.  There is not one that I can pull out to fix the problem.  If I pull out ST8 and ST9, the problem is gone but there are lots of missing elements.

I focused on the pink lines running through the text.  In the first picture, you can see that the pink lines are running through both the "GAME OVER" text and the Score text at the top of the screen.



If I remove ST9, the "GAME OVER" in the middle of the screen doesn't have the pink lines but the Score/Hi-Score elements do have the pink lines.

If I remove ST8, "GAME OVER" does have pink lines but the Score/Hi-Score doesn't:



Could both of these ROMs be bad?  Or is something else going on?

[pdp80]

The issue was the B-board itself.  I found another one and swapped the ROMs/PALs/C-board and the lines went away.