View Full Version : newbie-need help with imac g5,shutting off

Sep 19, 2009, 10:19 PM
im looking at buying an imac g5 on ebay, and the guy says "As of a couple of months ago, computer started acting up. I believe the issue is the logic board/heat, but have not had it looked at professionally or in an Apple Store. The computer will power on for about 20-25 minutes initially, then each time the machine powers off, the time is shorter. Everything has been erased off the hard drive, and returned to original settings.", does anyone know whats wrong with it? so i dont buy it and end up not being able to fix it

Sep 20, 2009, 01:12 PM
Likely problem is the PSU (power supply unit) or it could also be issues with failed logic board components, typically the defective capacitors that Apple and other computer makers got stuck with back in the middle of this decade.

Sep 20, 2009, 01:41 PM
how long is the warranty for these? and is there a way to test what exactly is causing the problem?

Sep 20, 2009, 01:43 PM
how long is the warranty for these? and is there a way to test what exactly is causing the problem?

The warranty was probably expired 5 years ago.

Sep 20, 2009, 02:08 PM
There are LEDs built onto the logic board that can provide a minimal level of diagnostics. On the pre-iSight G5 iMac, you remove the back cover, attach the power chord and boot the system. Whether any or all of the LEDs light up will help zero in on the suspected problem area. Apple's support site has a file that decodes the LED sequence.

Sep 20, 2009, 03:16 PM
The warranty was probably expired 5 years ago.

the g5's are that old? haha is that a good deal at what im looking at?...imac g5, 2.0ghz 160gb hdd,comes with wireless keyboard and mouse and all the cds and i think manuals. he wants $155 for it

Sep 20, 2009, 04:27 PM
i have a g5 imac - one before the isight.

it had problems where it shut off after 6-8 hours. you could power it on again and it would shut down again after a shorter time - not sure how long.

after a lot of trial and error i found the problem was the psu overheating - possibly due to the capacitor problem people have mentioned.

I found that if i removed the psu out of the case, fixed it to the aluminium foot and used an extension cable back to the logic board that did the trick - it seems to let the psu stay cool enough.

i've left it running for 48 hours solid with no issues. the aluminium foot has the added advantage of being a heat sink.

the difference is i had an imac which i'd paid a lot for and didn't think i'd got enough use out of it - whereas youre thinking about taking a gamble.

if it were me i'd give your one a pass, unless it was going to be a side project and not my only mac. that way you can take your time to try different solutions.

also you have to be in a position where you were prepared to write off the $155 if you couldn't get it working, although you might be able to strip it and sell the parts but tbh that's often a lot of work.