Mac g5 Powerpc REboot problem

Hi all.

I have a reoccuring problem with a G5 I bought about 5 years ago from a now defunct dealer. This problem has occurred several times over its life and Im stumped. Basically in a nut shell the machine wont reboot. It also wont boot if I shut it down and try to start it back up at anytime within a couple of hours of shutting down. If I leave it overnight it generally does boot up after that.

Im Positive it isnt a hard drive issue as Ive replaced the hard drive 3 times after thinking that was the cause (initially, when it would hang I could get it to boot from the OSX disc so figured it was a hard drive issue as when I ran a diagnostic it showed a problem with the drive - bad sectors or something I cant remember). After its 3rd drive and the same problem recurring, it became apparent that if I left the machine switched off for a period of time, it would boot without issue.

Does anyone have any clue what this might be, or has anyone had this issue and solved the problem?

Cheers
Andy

G'day and welcome to the forums.

Assuming your G5 is not a liquid cooled model as leaking coolant also causes this problem, your post does not say and that helps enormously to provide all information, sounds like you have a dodgy power supply which was a failing on early G5;s such as the 1.6, 1.8, 2 and 2GHz DP's.

harryb2448 said:

G'day and welcome to the forums.

Assuming your G5 is not a liquid cooled model as leaking coolant also causes this problem, your post does not say and that helps enormously to provide all information, sounds like you have a dodgy power supply which was a failing on early G5;s such as the 1.6, 1.8, 2 and 2GHz DP's.

Click to expand...

If it is, Its the noisiest liquid cooling system known to man!

Hi Harry and thanks for the reply. I get where you're coming from with the power supply, but its been doing this for maybe 4 years. I would have thought it would have packed up all together by now and like a beacon directed me to the root cause!

Tis a G5 Powerpc Dual 2.7 running OSX 10.5.8 (not that the OS would make a difference presumably)

Well the 2.7 is liquid cooled and when they leak that corrosive fluid gets into everything, including the logic board. Do a Google on this. Here is a start:-

http://lowendmac.com/ppc/power-macintosh-g5.html

Member baggss had this problem from memory with his liquid cooled G5 so when you see his avatar shoot him a PM.

harryb2448 said:

Well the 2.7 is liquid cooled and when they leak that corrosive fluid gets into everything, including the logic board. Do a Google on this. Here is a start:-

Power Mac G5 Index

Member baggss had this problem from memory with his liquid cooled G5 so when you see his avatar shoot him a PM.

Click to expand...

Well, on Googling it would appear the most obvious explaination. The Symptoms certainly tie up. Im absolutley gobsmacked to find its liquid cooled judging by the racket the fans make, but there you go, a symptom. Thanks alot for your Help Harry, much appreciated.

I have no Idea what to do now however, this sounds expensive!

dxps said:

Well, on Googling it would appear the most obvious explaination. The Symptoms certainly tie up. Im absolutley gobsmacked to find its liquid cooled judging by the racket the fans make, but there you go, a symptom. Thanks alot for your Help Harry, much appreciated.

I have no Idea what to do now however, this sounds expensive!

Click to expand...

Yupp...the Powermac G5 dual 2.7 definitely has a liquid cooling system. You may find these links an interesting read:

PowerMac G5 Coolant Leaks/Repairs

PowerMac G5 Coolant Leak Repair/Overhaul (w/photos)

...if you notice, both articles mention the Powermac G5 dual 2.7ghz.

I'm not sure if you've ever opened up your Powermac G5...but there is some pretty serious plumbing on the inside for the liquid cooling system...which is pretty hard to miss.

Good luck,

- Nick

Sorry but yes it will be very expensive and not worth the cost alas! Rather than repairs suggest you start considering putting the money towards an Intel machine.