Display Problems on iMac! Please help

[davidsonwildcat]

Can anyone help me diagnose this problem? This is what happens to my screen after using this computer for more than an hour. I know it's not a display problem because when I connect the iMac to my TV, I see the same problem on the other display.

Can anyone please help me diagnose this/suggest some troubleshooting tips? I'm out of Applecare

Thanks!

 

[malvicus]

If you see this problem on a different display, then it is most likely a video card problem. Unfortunately, you can't just replace the card. You have to replace the entire logic board. If you don't have applecare (or if it has expired) then this is a pricey fix.

 

[dtjay7]

I had a similar problem on another iMac. It is maybe heat related. I put SMC fan control on it and increased the speed of the fans. That worked but it is a sign of a failing graphics processor. Yours may be something different but it may be worth a try.

 

[malvicus]

OOh ya, especially after an hour, it could most likely be fan related. The overheating could eventually result in damaged video card. If you take it in for repair, they can diagnose your cooling system. Repairing that may not be as pricey but I dunno. I'm no tech. Hopefully, repairing the fan and finding out that you don't have to replace your logic board is all that is needed.

 

[Johnf1285]

Image

Can anyone help me diagnose this problem? This is what happens to my screen after using this computer for more than an hour. I know it's not a display problem because when I connect the iMac to my TV, I see the same problem on the other display.

Can anyone please help me diagnose this/suggest some troubleshooting tips? I'm out of Applecare

Thanks!

Would this happen to be a 24" with the 8800gs card?

 

[GabrielBfoto]

I have the same problem on mi iMac late 2009 … could you fix the problem on yours ?

 

[Nguyen Duc Hieu]

Try a thorough dusting and cleaning on your iMac.
Then re-apply thermal grease on both CPU and GPU chips.
It may help with the over-heating issue on ancient iMacs.