Atari 2600 works great for 10 minutes then black screen

[madmansmith]

Hi guys. Just got into restoring my childhood Atari 2600 I got in 1981, and this site has helped me tremendously with all of its posts. But I can't seem to find a post with my specific issue.

 

My last issue was replacing the RIOT chip, as my player1 joystick would not go down. Once that got fixed, I was able to play the console, and now had a reason to leave it powered on longer. And I discovered that after maybe 10 minutes, my screen will go black. If I try to power off and on again, still get a black picture. This leads me to believe the issue is related to the console warming up somehow, maybe a specific component.

 

Once the machine is off for a while and cooled down I can play again. I can play for several minutes, then the console will go black again.

 

Would you have any suggestions. I really hope its a case of a cap or the 7805.

 

Your help would be greatly appreciated.

 

Madman.

[madmansmith]

Probably very important to note as well, When i replaced the RIOT, I also added a composite MOD, so the video is done via that, the RF modulator is gone.

[Keatah]

Cap + 7805 are good places to start. Also try reseating the chips. We'll go from there and start checking for cracked solder joints.

Edited December 3, 2015 by Keatah

[+Stephen Moss]

I doubt it would be the cap causing that, it could be a failing 7805 or a problem elsewhere that is drawing too much current resulting in the 7805 going into thermal shutdown or socket creep/dry joints as Keatah suggested.

Someone reported a similar issue last week, if you have not see the post in the Hardware forum ( http://atariage.com/forums/topic/246217-help-troubleshoot-2600-resetting/) I suggested several key areas for dry joints that would the most obvious to start with.

 

 

[Mef]

Hopefully just 7805 acting up. Before you replace it tho, try removing the screw & heatsink, clean the residue left from the old (possibly completely dried out now) thermal paste and apply a new layer.

I've had a very similar issue with one of my Juniors, which had the 7805 soldered slanted in such way that the screw to hold it down wouldn't fit thru the hole. So it didn't even touch that flat piece of motherboard that doubled as heatsink. The effect was is went black-screen every couple minutes because of the thermal shutdown of the regulator.

Edited December 4, 2015 by Mef