[destroypower]

Hi there. I just got a used iMac G5 from a reputable seller on ebay. When it showed up today I hooked it all up and had it on for about 30 minutes before the display went all out-of-whack. There were red lines going everywhere, everything was pixelated, and the computer was frozen. I turned it off and put my hand on it. It was burning hot. I let it cool down for a while then turned it back on. It worked again for about 30-60 minutes before it died again.

When I turned it on again (after it cooled down) I downloaded a temp monitor program. I've noticed that in about 30 minutes of using the computer the "graphics processor ambient air" and "graphics processor temperature" go up about 20"C. All the other temperatures stay relatively the same.

Any ideas on exactly what might be wrong?

Thanks.

[ferrija1]

It's definitely not over heating, 20*C is only about 70*F. Your video card could be broken, I'm not sure how to test it though...

[ThreeDee912]

The older G5 iMacs had a known problem with odd video output.

The iMac G5 Repair Extension Program for Video and Power Issues applies to first generation iMac G5 computers that have video or power-related issues as a result of a specific component failure. If your iMac G5 is exhibiting any of the symptoms listed below and your computer's serial number is within the noted ranges, your computer may be eligible for repair, free of charge.

Symptoms:
-Scrambled or distorted video
-No video
-No power

http://docs.info.apple.com/article.html?artnum=302181

Send it to Apple and they should repair it for free.