[moisture]

I am trying to troubleshoot an odd problem that I am pretty sure is at least largely a system problem, though it may well have a hardware component as well. I have been getting vertical stripes at certain locations on my PowerBook G4 (FW800) display. I have posted three pictures here to illustrate the problem. Briefly, they are vertical stripes of one pixel in width that affect brightness but not color. They occur only in certain locations that seem to be dictated by the OS: e.g., on the menu bar, on the title bar of inactive windows, on the Dock, etc. If I drag an inactive window, the stripes move with the window. The problem occurs in all user accounts, at all resolutions, with all possible numbers of colors. I attached an external LCD panel and the problem occurred there as well. I reinstalled 10.4.8 and it made no difference. I have done all the standard things like disk verification and repair, permissions verification and repair, fsck, etc. Apple Hardware Test gave me a VRAM error of 2ATI/1/4, but since the problem I am experiencing seems to have a definite software component, given the location and behavior of the stripes, the VRAM error may or may not be related. I have a thread going at MacFixIt (here) but no solutions have been recommended yet. I'd be grateful for any thoughts you may have. Let me know if I can provide more information.

[msuper69]

The pictures you posted are too small to see anything wrong.

[TETENAL]

Originally Posted by moisture 

Apple Hardware Test gave me a VRAM error of 2ATI/1/4

There you have your answer.

[CaptainHaddock]

Sounds exactly like a video ram issue. Quartz buffers the contents of your application window to the video card, and a malfunctioning section of ram changes those bytes, creating a visual aberration. That bad video memory "stays with the window", moving when the window moves.

[MartiNZ]

To me the vertical stripes have always been symptoms of a stuffed logic board, mainly because that's what has had to be replaced everytime I've had them, but I'd be interested to hear what happens here.

My 12" PowerBook has been useless for about six months now with the same symptoms and a very similar error number in diagnostics. It happened when the machine was one month out of warranty and I managed to get the logic board repair covered, but then it happened again 5 months later and I couldn't get it covered, and had no AppleCare .

As it would have been very expensive to replace and as it seemingly had a 'history' with the fault, the machine has just been sitting in its bag since then - it can start up, but then tends to lock up before long. Just in the last couple of weeks I've been trying to advance the situation, going for not a reasonable period of use under the consumer guarantees act in New Zealand, but Apple curiously don't seem interested hmmm.

[CaptainHaddock]

Originally Posted by MartiNZ 

To me the vertical stripes have always been symptoms of a stuffed logic board, mainly because that's what has had to be replaced everytime I've had them, but I'd be interested to hear what happens here.

That's probably because the video adapter and VRAM are soldered right onto the logic board in laptops.

[moisture]

The lower RAM slot died shortly after this discussion. Apple replaced the logic board. All's well now. Thanks for the input.