IMac G5 random shutdown, won't restart

Question

Increasingly, my early 17-inch iMac G5 randomly shuts down, and the only way I've found to restart it is to unplug everything — power, printer, ethernet (cable modem), firewire backup disc, Palm cradle — and then plug everything back in. Then the light on the front of the computer comes back on and it restarts. There's no disconcerting odor, no odd noises. It seems to happen when the computer's been left alone and sleeping. What's wrong? What can I do to stop this? I don't know whether it's a hardware problem or a software problem. Thanks for any suggestions you have.

Answer 1

For me, it was several failures of each affected component.
So, it was a Power Supply, a logic board, a LCD Screen, keyboard, etc.
They just had a lot of faulty parts.
The problem was that they were sending out refurbished parts for the repairs (which is their standard practice). So, we were getting parts that they thought they had fixed, but still actually had problems that had slipped past their refurbishing process.
So, we may have gotten a refurbished part that had been fixed enough to pass their short test, but not fixed enough to survive actual long-term use.
With the power supplies, they did eventually switch to another manufacturer for the replacements. So, any replacement you get now, should be a better power supply.
But, any other part will be a refurbished version of the original parts that were used in the first systems.
Since they switched to another brand of power supply, I would not expect to have repeating problems with those.
But, if your logic-board were acting-up, I would expect your odds are 50 / 50 as to whether the replacement would later have problems as well since it is not a new design but a fixed original product.
Hope this helps.