Rev B iMac G5 power supply failures (#2)
Rev B iMac G5 power supply failures (#2)
We continue to report on power supply failures involving revision B iMac G5s (Ambient Light Sensor) that are not covered by Apple's iMac G5 Repair Extension Program for Video and Power Issues -- which applies only to first generation iMac G5 computers that have video or power-related issues as a result of a specific component failure.
Users experiencing these issues generally must replace one of two hardware components: the power supply, or the "mid-plane" assembly which consists of the motherboard and other circuitry. In most cases, users whose machines are still under warranty or AppleCare are able to quickly obtain replacement parts that resolve the issue.
In some cases, the serial number of Rev B machines falls into the range Apple has designated for repairs.
MacFixIt reader Carl Sanchez writes:
"I have a 2.0GHz ambient light sensor iMac purchased end of August. My serial number falls in the serial number range of the Repair program but second generation models aren't included.
"In October of last year the video starting dimming very noticeably like in a PowerBook trying to conserve battery life but would not brighten unless restarted, which didn't always fix the video problem. After about a week of this the iMac would just shut down. It would happen in the middle of activity. Then on restart the iMac just shutdown in the boot process, even sometimes after going to sleep I would come back and machine would be off Apple hardware tests looped for 6-7 hours showed no problems with logic board, power supply, or RAM. Problems would happen with original RAM and upgraded RAM.
"The local Apple store initially planned to replace both power supply and logic board. However after changing power supply they thought all was well on their tests and I picked up my iMac. Next day video began dimming again. Brought it back and at this point they replaced the logic board.
"All was well until two weeks ago and computer just started shutting down again. So now iMac is back in for a new power supply and possibly a new logic board. Strange that 2 power supplies where defective."
Peegee Whone adds:
"After only 3 1/2 months my G5 iMac (pre-built-in iSight version) started to turn off at irregular intervals. No crash, it would just die, as if I'd pulled the plug out of the wall. It got to the point where, after a restart, it wouldn't stay up long enough to log-in again.
"I took it to my local official Apple-Fix-It shop and suggested the power-supply was faulty. They first ordered a new mother-board, and when that didn't fix the problem, they took my original suggestion, and ordered a new power-supply. That seems to have done the trick. But it meant I had to endure 11 days of Mac-less-ness."
Feedback? Late-breakers@macfixit.com.
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