Atari Cojag hardware troubleshooting doc

[channelmaniac]

Had a PITA on the bench and got it fixed... Made a good one out of 2 bad boards. Both dead. Reprogrammed a bad ROM and was left with that one crashing left and right. Reflowed DSP/CPU chips and it stabilized but still crashed badly while popping up random errors about Bank 0 and found a missing signal. Replaced a bad GAL then had problems with sound/graphics, but it ran. It was missing a signal because I missed a pin when reflowing the replacement GAL onto the board. Oops. Fixed that and had fun playing the game.

In the meantime, I backtracked all the RAM control signals, figured out what is proper and improper on the Power On Self Test screen, and documented it all.

Hope it helps you keep your boards running.

RJ

DOH... too big for this forum so here's a link to it on KLOV...

 

[Asure]

I have one since 5-7 years that had a bad HDD but booted fine. Then i burned the patched roms and after that, it just blackscreens, tried everything i could think of, but it never booted anymore (even with original roms).

I cannot see your post on KLOV, even if i check your user/posts it seems to be missing. "no access" when i click the link.

 

[channelmaniac]

OOPS... Fixed it. It was a link to a PM. I put the post out on the open forum and attached the file there.