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Ashik, Mac Technician
Category: Mac
Satisfied Customers: 10937
Experience:  Bachelor of Computer Application (BCA), 9+ Years of Experience in troubleshooting Macs, iPhone, iPad, iPod etc
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My iMAC G5 Power PC has an intermittent problem. Occasionally

Resolved Question:

My iMAC G5 Power PC has an intermittent problem. Occasionally the display shows an irregular matrix of dots in rectangular shapes, and often this leads on to break-up of windows and a request to power down. Some days this happens several times and some days not at all.

Techtools suite does not find a problem. However when testing the video display with a pure yellow fill I can seen horizontal black lines flashing by when I click the mouse.
Any advice will be appreciated
Submitted: 8 years ago.
Category: Mac
Expert:  Ashik replied 8 years ago.
Hi I am Ashik. I think i can help you
I saw this problem on many Mac's (Mostly G5s) and it will result in either the replace of either logic board or graphic card repair. So to make sure this is not a hardware issue, you can create a new user account. So goto System Preferences and open Accounts. Create a new Administrator account and restart your Mac. now login with the new account and if the problem still exists, then it might me the hardware issue.

There is a another chance that, the problem is related to not only Graphics card but also to Logic board. Replacement of both Graphics Card or Logic board is very costly.

So my recommendation is, take it to the Apple store directly and ask them to repair it or replace. It is better to take it to the Authorized apple store and not to local computer shops. Since, this is a hardware issue only Apple can help you.

Apple Retail Store

Apple Authorized Service Provider

If you have any more questions, please feel free to reply back to this post. Good Luck !

Best Regards,

...If you are happy with my answer, please kindly click ACCEPT. If not, reply back before Accepting. Bonus and Positive Feedback are greatly appreciated. Thanks
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