iMac G5 PPC crashing - video problem?

[bip]

I've got a 2005 iMac G5 PowerPC 1.8GHz running Leopard. It's been running absolutely fine since I had it (upgraded to Leopard for at least 18 months) but randomly a week or two ago it's started crashing. Sometimes two or three times in a row, then it's been 2-3 days without problem.

The display starts flickering, usually the mouse pointer can still be moved but after 10-20 seconds or so it will just crash and I have to restart by holding the power button down.

There's nothing in the crash log. I've run the hardware test and checked the memory and everything is looking fine. I've completely reinstalled Leopard and also cleaned out the fan in case it was overheating that was causing this.

Managed to take a few screen grabs.

Any ideas? At a loss as to what's causing this.

 

[666sheep]

It's graphics card. Dying or overheating. You can replace its thermal compound with new one (in case if it's overheating problem).

 

[dantesays]

logic board

I had the same issue with my imac G5 and it ended up being two leaking capacitors on the logic board (a known issue with the imac G5s).

See this guide for more info on the issue (shows you how to check if the capacitors are leaking), and a possible DIY fix.

My suggestion, if you haven't already, is to backup your machine as soon as possible, in case the logic board completely fails.

 

[OrangeSVTguy]

Two most common problems: graphics card and/or capacitors. I have my 1.8ghz 17" iMac in for repairs at the moment for it's graphics card. It's getting reballed and resoldered. All my caps looked good. I tried cleaning/applying new thermal paste but that didn't do much. Still displayed lines on the screen so the damage has already been done.

 

[d88co88]

Wouldn't this be a software issue because you couldn't take screen grabs of a hardware related issue? Try an archive and install.

EDIT: Sorry OP, saw you had already tried re-installing.

 

[bip]

ok thanks guys.

seems it's the capacitors. will try to see if i can get someone to replace them for me and hope that sorts it, or at least means it doesn't happen as often.

 

[raysfan81]

ok thanks guys.

seems it's the capacitors. will try to see if i can get someone to replace them for me and hope that sorts it, or at least means it doesn't happen as often.

If/when you get it replaced ask the person who does it to re apply thermal grease to major components because of the high temperatures those models where famous for. It could help prevent future overheating issues and improve the longevity of the computer.

 

[jgmilberg]

Hey Bip, did you ever get your imac fixed? I'm having the same issues, and was wondering what capacitors needed replacing, and if they were obviously shot/blown up or did you have to test for them.

 

[bip]

afraid not. the local mac store was going to fix it (free of charge IIRC) but couldn't get the part and wouldn't use a second hand part. I found a few places online that would fix it but I think it would have cost me £100+ so I just stuck it on eBay and sold it for parts and ploughed the cash I would've spent on repairing it on a new iMac.