Imac Isight G5 PSU repair

[fleater]

Re: Imac Isight G5 PSU repair

Great to see this as I now have the same issue...... Great site.
Fleater

[fleater]

Re: Imac Isight G5 PSU repair

The Imac light just blink.. nothing else is happening when I push the "ON" button.

I know its late but this is from the Imac LED diagnosis section....

Intel-based Macs such as the iMac (Early 2006) rely on a combination of tones and blinking LEDs to display Power On Self Test (POST) error codes.

If the computer detects out-of-specification memory or no RAM installed, the screen will be black and the power LED on the front of the computer will blink once a second to indicate bad or no RAM. Bad RAM can include physically damaged, the incorrect type, or not present.
If the RAM is good enough to pass the POST test but it is marginal and cannot be used by the operating system, the computer will show a gray screen, three tones will sound and the power LED on the front of the computer will blink three times, pause, and repeat until the computer is turned off.
The solution to both these situations is to install known good memory.

[trex66]

Re: Imac Isight G5 PSU repair

If the Imac just blinks when you try to start up it's not the PSU, it's the computer. Re-seat the memory should give you post. Also, it must have some RAM to start up, there is no internal RAM like Apple used to include. For intel Imacs running os 10.5.x you need 1Gb, if it is 10.6.x you need 2Gb.


Looks like Fleater found the answer, Macs are very pickey about the memory they use. I have bought new RAM that didn't work in an Imac but would in other computers.

The PSU's from the isight on are pretty stable, not like the older ones. In fact, I have never seen a bad PSU from Isight and newer Imac - I know there must be some, just saying not a common problem like pre-Isight.

[Sideshow Bob]

Re: Imac Isight G5 PSU repair

Hi, if anyone is still following this thread - I've just been asked to fix a G5 (same model) and my PSU gives no reading between Black & Grey whatsoever. The Brown (PFW) gives a fluctuating reading - to fast to read on my slow digital meter screen but it alternates from volts to milli-volts.
There's no sign of popped caps however I was told there was a 'bang' and a slight smell of burning whilst it had been left (presumably) on standby one night.

Can anyone confirm that this PSU is dead and is it fixable? I'm going to remove the motherboard in my continuing quest to find evidence of a 'bang' and I'll report back...

I'm not used to Macs so any help would be greatly appreciated!

Cheers - Bob.

[Toasty]

Re: Imac Isight G5 PSU repair

These units provide a constant 12vdc to the system. They sense the system being turned on and come up to full power once a load above 0.2 amperes is presented. A 194 automotive marker lamp works well. Below that they provide 12v, but the current is low and the 12v may appear to "wobble". {An analog meter will show this clearly}

Use you nose to find the burnt components. Look at the back and see if any blew up.

T