iMac PowerPC G5 requires several reboots before up and running?

[imacpowerpc]

Hi all

There still seem to be quite a few powerpc users on the site who are perhaps like myself and just can't quite bare to give them up just yet...

The problem is simple with my old girl, my imac has decided to start spontaneously powering down midway through booting usually around the apple logo stage and sometimes a few moments later just before the desktop would usually appear. I reboot a number of times and after around 4 or 5 reboots(it was after 2 or 3 but it's clearly getting worse) it makes it on to the desktop and we're up and running. The screen crackles(I can't think of a better expression or it at the moment..?) as I move the mouse around for a few minutes then after that all is well..

In my laymen terms it seems as though something is having to warm up first with the several boots before it finally gets going? Maybe it needs to be wrapped in a warm blanket first before it'll work?

This problem may resemble the frequently posted about PSU issues, however I've done the mac diagnostics test and all is well on all fronts. I have not been able to find anything on any sites as to what this might be so I guess it could be a new one?!

Any help much appreciated!

 

[4Hummer]

Sounds like some bad capacitors in the power supply or on the motherboard.

Google is your friend. their are a ton of threads on this

Found one: http://m.instructables.com/id/Imac-G5-DIY-capacitors-repair/

Super easy to check and repair.
I had to replace 3 caps on the motherboard. Exact same symptoms as you

 

[imacpowerpc]

Sounds like some bad capacitors in the power supply or on the motherboard.

Google is your friend. their are a ton of threads on this

Found one: http://m.instructables.com/id/Imac-G5-DIY-capacitors-repair/

Super easy to check and repair.
I had to replace 3 caps on the motherboard. Exact same symptoms as you

Thanks 4Hummer - yep I had a look through these sites and thought my problem was different as my diagnostics test was fine and showing the PSU as being okay, my understanding is if the caps are blown the test should show a faulty PSU? I got this from this website http://jimwarholic.com/2008/11/apple-imac-g5-power-supply-issues-and.php

The symptoms do suggest a faulty PSU so unless anyone's got any alternative suggestions i'll crack open the PSU I suppose and check out the caps..... This might be taking my level of interest in imac PSUs to a new profound level, but i think i'll stop short of changing the caps myself..

Cheers