Imac G5 with shut down problem, out of Apple repair period, any easy fix?

[motulist]

Someone in a different forum is selling one of those iMac G5's with the power problems that cause it to suddenly shut off after a few minutes of use. Is there any easy and cheap fix to this problem that would make buying it worthwhile? I don't mind if the fix is ugly or inelegant, I just want it to work reasonably reliably. Does anyone know what the actual cause of these shut downs is? Searching the MR forum, I read something about how maybe a capacitor on the power supply is the problem, someone else said maybe it's a problem with the logic board, but I couldn't find a definitive answer. I'm thinking that if the problem is simply overheating due to a faulty component, then I could just run it with the back of the case off and add a couple of fans. So I need to know, is there any cheap and easy solution that would fix this problem?

He's asking 100 bucks for it, but I think I could probably talk him even lower.

p.s. The special extended Apple repair program that was offered to fix these machines seems to be over according to this page I found.

 

[Schtumple]

Weren't those machines the ones with the self serviceable parts?

http://www.dvwarehouse.com/iMac-G5-Power-Supply-c-253_238_247_4774.html

That what you need?

It's still a good deal if you fancy fixing it yourself.

 

[motulist]

Hmm, that's a good lead. But do we know if the problem really was always a faulty power supply? Searching the MR forum had people saying Apple was claiming the problem was their power supply, and other people said Apple claimed it was the logic board, someone else said something about some faulty capacitor somewhere. If all I need to do is replace the power supply, then I'm certainly capable and adventurous enough to do that myself. But I'd hate to buy this iMac, and a new power supply for it, and after all that still wind up with a machine that turns off after a few minutes. He said I could check out the machine in person before I buy it. Is there any way I can verify which component is causing the problem in this particular machine's power system before I buy it?

 

[suburbia]

I own the iMac G5 with that problem you're referring to: It was the power supply. But there's no way of knowing exactly what the problem was; it was a process-of-elimination diagnosis-- if replacing the power supply didn't remedy the problem, then the next step would be to replace the logic board.

You would be taking a gamble by purchasing that iMac G5.

 

[StealthRider]

You'd be better off going for a refurb or PowerMax used machine - you don't need the hassle of buying a DIY fix-it computer.

 

[bizzle]

It's actually very easy to see what part is the one with the issue, usually. Look at the capacitors on the main logic and if any are bulging or leaking, it's the board.

 

[motulist]

You'd be better off going for a refurb or PowerMax used machine - you don't need the hassle of buying a DIY fix-it computer.

The lowest prices I've found for a G5 iMac are in the low to mid $400 range, which is in a whole different price ballpark. All my machines are G4s, so this would be a significant upgrade that would be enjoyable, but isn't really necessary. So buying a used iMac G5 from a store is out. I'm interested in buying this machine not because I need another Mac, but rather because this particular deal is very low priced, so if I could get it to work then it would be a steal that I couldn't resist. But that's only if I wind up with a working iMac G5 for cheap at the end.

Is there anyway to determine which component was the point of failure? One MR forum post said they saw visible burn marks on their logical board. Are there burn marks on every logic board that had power failures, or just some? More importantly, is the cause of the power problems in either case (logic board or power supply) due to an electrical problem directly, or an overheating that results from that problem? Because if it's just an overheating issue in either case then I'd be almost just as happy to run the thing with the back of the case removed and a couple of extra fans attached.

 

[motulist]

It's actually very easy to see what part is the one with the issue, usually. Look at the capacitors on the main logic and if any are bulging or leaking, it's the board.

Do the capacitors always bulge or leak on the failing logic boards, or just sometimes? And are all the capacitors visible on the back-facing side of the logic board, or are there capacitors on the screen-facing side of the logic board also which I would need to disassemble the entire machine so I could see them? What causes the capacitors to fail, is it excessive heat that could be fixed by an extra fan, or is it a hardwired (i.e. unfixable) electrical problem?

 

[bizzle]

Do the capacitors always bulge or leak on the failing logic boards, or just sometimes? And are all the capacitors visible on the back-facing side of the logic board, or are there capacitors on the screen-facing side of the logic board also which I would need to disassemble the entire machine so I could see them? What causes the capacitors to fail, is it excessive heat that could be fixed by an extra fan, or is it a hardwired (i.e. unfixable) electrical problem?

For the symptoms you're describing and the caps are bulging, it's the issue (plus the power supply potentially). They fail most likely due to using low quality capacitors. You can see them from just popping off the back. Once the capacitors are bulging you need to replace them yourself (which is possible) or replace the logic board.

Also check for shutdowns in your logs with -110 for the number, that usually means the power supply is bad and potentially your board.

 

[motulist]

For the symptoms you're describing and the caps are bulging, it's the issue (plus the power supply potentially). They fail most likely due to using low quality capacitors. You can see them from just popping off the back. Once the capacitors are bulging you need to replace them yourself (which is possible) or replace the logic board.

Also check for shutdowns in your logs with -110 for the number, that usually means the power supply is bad and potentially your board.

Thanks for all the great info. It sounds like this deal is way too iffy, I'm gonna pass. Thanks everybody.

 

[neilw]

I just replaced the power supply on mine the other day, and fixed the shut-down problem which had cropped up quite suddenly. I looked at the motherboard, saw no bad caps, and so ordered a new power supply for $120 and crossed my fingers. The new supply solved the problem perfectly.

If the problem had been the motherboard, I'd have been in a pickle, because $400 or $500 or whatever a new one costs would totally have been not worth it, and I really didn't want to be forced to upgrade quite yet, what with the new revision allegedly on the the way.

Still not happy that I had to lay out over $100 for a machine nearing the end of its life, but at least it's working again.

 

[bizzle]

I just replaced the power supply on mine the other day, and fixed the shut-down problem which had cropped up quite suddenly. I looked at the motherboard, saw no bad caps, and so ordered a new power supply for $120 and crossed my fingers. The new supply solved the problem perfectly.

If the problem had been the motherboard, I'd have been in a pickle, because $400 or $500 or whatever a new one costs would totally have been not worth it, and I really didn't want to be forced to upgrade quite yet, what with the new revision allegedly on the the way.

Still not happy that I had to lay out over $100 for a machine nearing the end of its life, but at least it's working again.

A $120 repair for a computer that's 3-4 years old is pretty damn good. I wouldn't complain.