Non Running PowerMAC G5 help with refurb needed

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chriss1964

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I've recently obtained a 2004 Model Dual Processor 2GHz PowerMac G5.

I've tried powering it up with a standard USB keyboard (not mac) and USB mouse.

I get a lit white LED on the power button but nothing on the display.

Could anyone point me towards any info regarding diagnosing how to get the machine going.

Would a non mac keyboard cause it not to start up?

Any help gratefully received, this is my first attempt at working on a Mac, so I'm totally unfamiliar with what to expect.

Ta.
 
Start with replacing the PRAM battery. It'll look like 1/2 of a AA cell. Radio Shack should have them. Also, while in there push the reset button near the battery. It'll be a very small (c. 1/8") black round button.

Come back if those 2 don't help.
 
The reset button on an old PowerMac G5 is nowhere near the battery. The battery is near the top of the logic board. The reset button is near the bottom, underneath the ram slots.

Do the fans run, and do you hear the boot chime sound shortly after pressing and releasing the power button?

Be sure to try reseating the video card.
 
Right, so reseated the video card, blew a lot of dust out of the case, plugged in a std usb mouse and keyboard and....

Bingo! A slighly long wait and up it came. Really pleased.

I had to press a key on the keyboard first time, it then recognised the keyboard and seems to remember it.

Its amazing what companies throw in skips...

Thanks
 
I got the Mac out of a pile of scrap computers that my company was disposing of...

Its now fully updated and looks like its going to be a great machine for me.
 
Hi Folks, here's a quick update with my story of my recovered Mac.

After what appeared to be an initial success I had an issue with the machine 'freezing' after a few minutes use. I've noticed that this seems to be a common issue for people with G5's so here's what I did to solve the problem.

I stripped the machine down completely (I'm an engineer so this wasn't really a big deal for me, but you do need a few tools like a long 2.5mm allen key, philips screwdriver, nothing serious. Always try and observe anti static precautions when you strip a system down, ideally do it on a dissipative mat with a wrist strap to ground.

So once I had the motherboard out of the box a problem was clearly apparent. There is a custom chip on the back of the board which may be some kind of memory controller or bridge. This has a heatsink and associated heatpipe assembly.

The heatsink is secured by 2 springloaded plastic lugs. These had both become unclipped and were not able to retain the heatsink in place. The custom chip was therefore clearly not being cooled correctly.

So I cleaned the old heatsink compound away and applied new, then replaced the plastic lugs with 2 off 3mm x 12mm nylon bolts, tightened it all up and reassembled the system.

The machine booted happily first time and has now run for several days without problems, I have restarted the machine several times and have not experienced any 3 flashes of the LED symptoms or any failures to boot up.

So I'm now pretty confident that this has fixed my machine, I can't guarantee it will solve all of these but its definitely worth a look.

In fact, the problem can probably be diagnosed without disassembly. If you look at the main board between the sets of rams, and towards the processors you will see a cluster of components, these are the decoupling passives for the custom chip. The ends of the 2 plastic lugs should be poking through the board 3 or 4 mm at two corners of the cluster. If the lugs aren't sticking through then the heatsink will be loose and the custom chip won't be cooling properly.

Hope this is useful info for someone.
 
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