[sd]

I have an iMac 800Mhz 15" and it's crashing at a very frequent rate. This has started to happen in the last month or so. The machine came with a stock 256M from Apple to which I added another 512M from Crucial at the same time that I bought it. It's been working fine since up till now.

Sometines the machines freezes up and displays the grey box telling you to power down but in a majority of cases the screen gets scrambled. Parts of the display show up at different positions on the screen and parts of the display show red, green and blue lines in blocks either horizontally or vertically. If you try to select a region with the mouse the area becomes completely scrambled.

The machine is out of warranty and Apple thinks it may be the logic board. The cost of this is $300 plus $140 labor and this comes with a 90 day warranty.

Has anyone experienced something similar to this? Is it worth repairing or selling it on ebay noting the problems and selling it "AS IS".

[f1000]

Try running the Hardware Test from your Apple Install disk and post back with the results.

[sd]

The hardware test does not report any problems. I've run the extended tests over and over again. In all cases no problem was reported.

I have noticed that playing DVD's, having flash running in Safari or running intensive OpenGL applications seem to cause the problem almost instantly. Basic browsing and email does not seem to cause the problem.

[P]

Have you tried running Disk Utility? Do it when booted from the install CD for best results. You could have a damaged disk (like I do right now...)

[sd]

I've tried it but not when booted from the install CD. I'll try that, thanks.

I found exact problems on the Apple Discussion boards and the concensus was a faullty logic board. I'll try the above nonetheless.

[Randman]

Did you try removing the ram? I'd make sure it wasn't that before opting for a faulty logic board.

[sd]

I've removed the RAM that's user installable. I'd installed this at the time I bought the machine, I bought it from Crucial. I don't believe the other slot is accessible.

Interestingly though, when I removed the RAM the machine crashed at a greater rate than before.

Ran Disk Utility from the CD. No problem reported.

[f1000]

Try running DiskWarrior instead.

[P]

Originally posted by sd:
Interestingly though, when I removed the RAM the machine crashed at a greater rate than before.

Ah. Try removing the other circuit, the one Apple shipped.

[sd]

How do I do that? It doesn't seem to be accessible when I open the base plate. Do I have to take the machine apart?

[bkb]

A friend of mine had the same problem you are having. The Genius couldn't find the problem - there was no problem being reported on the Extended Test. They shipped it to a repair center. The motherboard was faulty, it took a couple weeks but now his computer is back and it's working fine. i suggest you get someone to check it out. remember to de-authorize your purchased music, if you have any.

BKB.

[sd]

Originally posted by bkb:
A friend of mine had the same problem you are having. The Genius couldn't find the problem - there was no problem being reported on the Extended Test. They shipped it to a repair center. The motherboard was faulty, it took a couple weeks but now his computer is back and it's working fine. i suggest you get someone to check it out. remember to de-authorize your purchased music, if you have any.

BKB.

This is also what the genius at the Apple store said. My problem is deciding whether to spend $440 on the repair (this is what he quoted me) or buy a new iMac.

[bstone]

Originally posted by sd:
This is also what the genius at the Apple store said. My problem is deciding whether to spend $440 on the repair (this is what he quoted me) or buy a new iMac.

From this I take you did not purchase AppleCare. Had you done this the repair would be entirely free, unless it was through user fault (spilling water on the computer, dropping it, etc)

Moral of the story: Always, always, always buy AppleCare.