[diehlr]

Well, the green light of death problem is solved, now I'm working on troubleshooting another issue that's been rearing its ugly head on this CRT for quite some time. The picture tends to get very unstable, not wiggly or jittery, per se, but horizontally unstable. Almost as if there is noise horizontally along the image (but not vertical). Almost looks like the horizontal sync is a little wacked out. Sometimes it only lasts for a second or two, sometimes the picture just gets noisy and stays that way for a while.

Has anyone else run across this problem in the old tray-loading iMacs? More specifically, rev A iMacs? Have any suggestions on where I should be poking around? I would guess I should start probing the video signals with an oscilloscope around the analog board until I find a clean input and a noisy output. But I was wondering if there is a common point of failure on this particular model that will give these symptoms.

PS- Please don't suggest firmware updates, this has nothing at all to do with firmware or software. Just a heads up.

Thanks.

[t1mmyb]

Originally posted by diehlr:
The picture tends to get very unstable, not wiggly or jittery, per se, but horizontally unstable. Almost as if there is noise horizontally along the image (but not vertical). Almost looks like the horizontal sync is a little wacked out. Sometimes it only lasts for a second or two, sometimes the picture just gets noisy and stays that way for a while.

Has anyone else run across this problem in the old tray-loading iMacs?

I've seen something similar in a 2000-model iMac DV+ 450MHz. Apparently it was a problem with that model. It's *much* better under Panther than it was under OS9, but still evident. It seems to get worse when the mouse button is pressed, for some reason.

HTH,

Tim