PowerMac G5 screens temporary stop working

Some PowerMac G5 users are experiencing problems wherein their screens will become nonfunctional for a period of time, before the monitor image will appear normally again and they can continue work.

Apple Discussions poster p_r_o_c_k writes:

"I've purchased a used Power Mac dual G5 2.0 and last night I noticed something troubling. The system would suddenly lockup (can't move mouse) for about 5 seconds, then the screen quickly fades/flashes blue (the same colour as the login page) then back to my desktop and I can continue working."

In addition to screens locking up and going blue, displays may randomly go black and then switch back on after a moment. This problem was first suspected to be caused by Leopard; however, some users are also experiencing it with systems running Tiger. There are several reasons why the monitor will randomly turn off or go blue.

Problematic Software One potential problem could be with a graphics driver or other software conflict in the system. If users have recently installed any software packages, especially utility or feature-enabling ("haxie") software, it is recommended to remove these packages. Some users have found that the popular "Stuffit" archive management suite has contributed to this problem, and disabling the Stuffit "AVR" feature in the system preferences has fixed the problem. If the problem persists despite removing these software packages, users should try reinstalling the operating system using an "Archive and Install" method.

Overheating Overheating of the graphics components can cause malfunctions, and it is recommended to ensure the graphics card and other system components have adequate air flow. Apple tower computers have exceptionally good ventilation, but if components have ample dust build-up, this can prevent proper airflow and also insulate the components, causing theme to overheat. It is recommended to periodically dust the insides of the computer with a can of compressed air, ensuring all heat sinks and fan blades are free of dust buildup. Additionally, ensure the computer has at least several inches of space around the front and rear vents.

Faulty Graphics Card The graphics card might be going bad, in which case replacing it should fix the problem. Unfortunately the only way to really test this is to replace the card, since as long as the card is temporarily working, hardware tests may not detect any problems. Some users have solved this problem by replacing their graphics cards.

Faulty Logic Board Beyond the card going bad, users may also have a faulty logic board. The video card is only one part of the graphics system, and faulty controllers on the logic board that interface with the graphics card could also cause these problems. If users have tried multiple video cards and still experience this problem, replacing the logic board would be the next step.

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