iMac 20" G5 Power Up Problem

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Hello.

First of all, great forum, glad to be here.

Now on to the problem!

I have acquired an imac g5 (a1076) that is puzzling me no end.

At first I thought it was a dead power supply as it was doing nothing when I was trying to switch it on, totally dead.

So I opened it up to check the LED's and LED1 was lit, which tells me its getting some power at least. So I tried pressing the internal power button, nothing, at first, then after a while and a few more presses, it fired up fine, with all 3 LED's lit.

So I turned it off, put it back together and at first few presses of the power button, nothing, then it started up and worked great. I tried a few restart cycles thru' OSX and it started back up no problem every time.

So I powered down and left it for half an hour, tried to restart, nothing again.

Repeated the whole back off process and finally it started again.

I've just tried it again after being switched off and unplugged for a couple of days and at first, no power. I left it 15 mins tried again and after about 3 or 4 presses of the power button(external button, not opened up) it started.

Im leaning towards a power supply on its way out or possibly logic board on its way out.

Am I right in thinking that LED1 & LED2 should be lit with the power cord attached but before power up? Because only LED1 is lit till it powers up then all 3 are lit.

I'd like to try and fix this but don't want to replace the power supply to find out its the board or the other way round!

Any help or ideas would be great

Cheers, Lee.
 

pigoo3

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Maybe a long shot...try testing/replacing the PRAM battery.

- Nick
 

pigoo3

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Put in a new battery, still the same problem I'm afraid

Thanks for the help anyway

Nice try!:) I did this on a "problem" iMac G5...and a new PRAM battery solved the problem. This iMac could very well have something more serious wrong with it.:(

Just curious...does anything happen when you turn this iMac on. For example...does the hard drive spin up at all?

- Nick
 
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Nice try!:) I did this on a "problem" iMac G5...and a new PRAM battery solved the problem. This iMac could very well have something more serious wrong with it.:(

Just curious...does anything happen when you turn this iMac on. For example...does the hard drive spin up at all?

- Nick

Sometimes it all comes on fine and boots to osx no problem.

When it doesn't start up, its totally dead, no chime, no hard drive activity, nothing except LED1 lit on the logic board.
 

pigoo3

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Sometimes it all comes on fine and boots to osx no problem.

When it doesn't start up, its totally dead, no chime, no hard drive activity, nothing except LED1 lit on the logic board.

What's the history of this iMac G5? Something you had for a while...and was running fine previously...and now has problems? Or did you just get it...and it has never run as it should?

- Nick
 

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