G4 iMac (800mhz) - No power

Hutchism · May 6, 2012

Hey all. I have an old 800mhz G4 iMac downstairs. Its been dead for some time now. Story is that I moved house and lost the power lead for it. Found a black lead which looked identical so tried to use that. Since then it's been totally dead, even using an official mac power lead.

It's an old comp, but wouldn't mind breathing some life back into it. Is there anything which I might be able to try to save it without spending money on a new powersupply. Haven't opened it up yet, but if anyone's got any bright ideas of a simple fix would be much appreciated.

harryb2448 · May 6, 2012

Alas bright ideas cost money!

Have you tried booting with a compatible mains power lead since?

Hutchism · May 6, 2012

Yeah, no joy with a compatible lead either. I'm assuming the mac doesn't have an integral fuse or something? Perhaps a blown capacitor?

I'd love to have some idea what might have gone so that maybe I can just replace that. I don't have such a good technical knowledge of these things, but I can test a current and replace a capacitor if I have to.

I brought the mac cheap some time ago, and its a neat little thing for playing music on, and having a useable machine sat there just for doing simple surfing and stuff on

harryb2448 · May 6, 2012

Have a look at the power supply. There could well be a fuse in there that has blown.

MacDude121 · May 7, 2012

It's most likely the power supply that has died, replacement for one of these is not very easy or cheap either. If you're really interested though, here's one:

Power Supply for iMac G4 15" LCD (700 & 800 Mhz) 661-3184 614-0147 - $84.95

Hutchism · May 8, 2012

Hey guys. Just an update: FIXED!

Ok I originally posted before doing any real trouble shooting and assumed the worst - that something had fried and wondering if anyone new what parts might be likely to fry first on the power supply.

The cause seems to be that because it was left unplugged for too long and the 1/2AA CMOS battery had died, preventing it from booting. Took the battery out and it booted first time.

New battery on order for £2.75 and happy days. The machine's only ever going to be used for playing music and maybe occasionally surfing the net, so £2.75 seems like a worthy investment

MacDude121 · May 8, 2012

Hutchism said:
Hey guys. Just an update: FIXED!

Ok I originally posted before doing any real trouble shooting and assumed the worst - that something had fried and wondering if anyone new what parts might be likely to fry first on the power supply.

The cause seems to be that because it was left unplugged for too long and the 1/2AA CMOS battery had died, preventing it from booting. Took the battery out and it booted first time.

New battery on order for £2.75 and happy days. The machine's only ever going to be used for playing music and maybe occasionally surfing the net, so £2.75 seems like a worthy investment

WOW! Very lucky fix indeed, the battery has been dead in my G4 iMac for years, never had an issue except the date would reset when it got unplugged.

Enjoy your iMac!