RAM error on Atari 4 player football

Vectorman

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Working on restoring a 4 player Football. Board kind of boots, but the "field" doesn't look right - kind of skips around and seems randomly put together.

In test mode, it says ROM ok RAM BAD. The manual is useless - it just says basically this means the ram test failed. Duh.

I painstakingly removed, socketed, and replaced all eight 22-pin 2101 RAMs....no change. I replaced the two 2114s...no change. I even replaced some odd 82s16 or something like that that was labeled a RAM on the schematic...no change.

Any ideas?

Thanks,
John
 
Your best bet is to throw a logic analyzer on the CPU and see what address is failing in the RAM test, since the test itself doesn't give any better info.

I wrote a better RAM/ROM test for 2p FB, but I don't know if it'd run on 4P.
 
Thanks for the suggestion...I would do it if I had a logic analyzer and knew how to use it. Are they easy to learn to use? I'll buy one if so...

I have no problem getting test equipment, but without someone to show me how to use it the stuff just sits. I've got a CAT box, PAT 9000, CTS 9000, and even a Kurz-Kasch test fixture. But virtually no documentation with any so they're all useless to me.

If anyone knows how to use all this stuff, I'd consider paying you to visit me for a day or two and train me on their use. Maybe I should start a thread on that idea...

One other piece of data. I hooked up my CAT box to it (which I really don't know how to use to be honest) and it gave me "E7" as the data when the RAM test failed. I don't exactly know what to do with that information. Any ideas?

John
 
Hmmm....this does have a very nasty edge connector.

Forgive my ignorance, but where do you get the parts to replace one of these ancient edge connectors? Does it require special crimping tools?

John
 
You should be able to find any edge connector you need from Bob Roberts. If you swap it, make sure you key the new connector. I just bought a 2 player, and whoever swapped the connector before I got it failed to idiot proof it. Then I bought it... I am trying to figure out how to test the board to find out what I fried from plugging it in backwards. All I have is a DMM and a logic probe. I wish I had the test equipment you have, but then of course I would need to learn how to use it as well. I never tried to use the logic probe before tonight, and it didn't help me much. I was checking the 7400 that is first in line from the watchdog line from the connector (it got +10vdc in the oops). I got lost with the pulsing stuff, it is beyond my one semester digital design class. I am taking am electronics and a microprocessor course in a week, so I am hoping to finally figure some of this out. :)

Good luck with your testing!
 
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