[blizzard]

Has anyone else ever experienced wavy or distorted video from a Power Mac G4? I just moved it from the top to the bottom of my desk and all of the sudden it's like I'm reading the entire display through water or something...everything's dancing around ever so slightly. This has happened with my dad's G3 before too...that was caused by a bad stick or RAM shorting the motherboard, I think, so i'm hoping my mobo isn't fried.

And it's not the monitor either...I tried plugging a different one in and the same thing occurred.

It's not the video card because I switched my flashed 2MX with the original Rage 128 and the same thing occurred.

And it's not the RAM because I pulled all the sticks one at a time and the same thing occurred.

Any ideas?

[reader50]

When you moved the monitor down, you most likely moved it closer to a source of EMF interference. Try moving it back up to the previous position. If the interference goes away, then you need to track down the source.

Options are to turn the source off, move the source, move the monitor, move the desk, add a shield between monitor and source, or build a complete Faraday cage around the desk (assuming the interference source is not in/on the desk).

If the interference is present in the original location now ... that sounds expensive. Though if you added anything on the same power strip when you reconfigured your desk, it could be putting noise into the computer on the ground line. That could cause interference regardless of monitor or vid card, without requiring the computer to be damaged.

[blizzard]

Thanks for the ideas...a couple of updates.

1.) I should have been more clear...I moved the computer from right beside my monitor (where everything was fine) to below my desk (where the problems started). In the process of troubleshooting I moved the computer back up to beside my monitor to see if that fixed anything, but the problem remained at the same level of intensity. So I can't see it being interference, although I'll certainly try shuffling things around to see if we can't make a difference.

2.) After playing around with it some more last night, I discovered that the problem varies with refresh rate. At 60 Hz, it's nonexistent...but my eyes want to jump out of their sockets at such a low refresh, so I can't very well leave it there. At 70 Hz, it waves around very slowly, like it's drunk or something. At 75 Hz, it moves around more quickly. At 85 Hz, it looks like it's on speed. And at 100 Hz, the problem disappears again. But at 100 Hz, I'm running a 19 inch monitor at 1024x768, so I don't like that option either.

Any further ideas?

[blizzard]

Final update: it turns out when I moved the computer around to see whether it was interference, I just didn't move it far enough. After doing some research on the Ars Technica forums, I tried moving the computer far enough away to be on a different circuit, and lo and behold the problem was solved! Now all I need to do is call my landlord and figure out how to fix the wiring in here.

Thanks for the help!