5200 console help?

[jc78_2005]

Hello. Long time member here been away from the scene for years just now trying to get back to collecting. Received a 5200 in a trade a few weeks ago .randomly with no pattern some times it will boot to garbled graphics as in the pic. Cart port is clean as are the cartridges and the results are the same with all carts. Then sometimes it boots just fine? Could his be a chip prob? Thanks!

[atari-dna]

Suspect the 6502 or ram chips may be problematic. Hard to diagnose without swapping chips. Display circuitry is obviously fine. Shouldn’t be too hard to figure out.

 

 

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[jc78_2005]

Finally tore into the console tonight. Pretty sure this was my issue. I removed the chip,and reinserted properly. So far after a few hours no issues.The rf shielding didnt appear to have been removed before so this really was a surprise !

[+-^CrossBow^-]

Actually that is normal for pin 11 on the GTIA to be pulled out on the 2 port models. Can't recall what or why it was done, but it was an Atari factory done thing to have that pin not in socket. I suspect you've gotten lucky with the carts working again thus far. If it comes back, you are looking at most likely a faulty video ram chip. Pretty common I'm afraid and part of the reason those chips are still in sockets even on the 2 port models like yours above. The Video ram is the bank of smaller chips to the left side of the main board.

[jc78_2005]

Thanks for the heads up! I may go ahead and order the ram chips just to have them on hand for if and when the problem returns.

[+-^CrossBow^-]

All you have to do on those is change them out 1 by 1. If you had a diagnostic cart it would essentially tell you which ram chip was at fault. Without one, you just take one of the good known ones and start swapping it one by one until the issue clears or changes. Then start over if more than one is bad.