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InfoTime
Aug 23, 2011, 01:43 PM
Trying to determine what's wrong with a Power Mac G5 (June 2004).

The user went to reboot it the other day after installing some drivers for his GPS. It shut down normally, but wouldn't chime and start up again.

I've tried:
- unplugging everything and letting it sit for a minute or so (to reset the PMU?)
- remove the battery from the motherboard, hold down the power button for 15-20 seconds. Then try to turn back on.
- measured voltage on the battery is 3.60. Markings on battery indicate 3.6V
- removed and reseated 3 of the 6 memory DIMMs. Was going to try to remove the power connector to the motherboard, but decided to try that later

Observations:
- user said that after a power failure in the home he'd have to reset the date and time
- machine will power on, no chime, sit for a while, after several minutes the fans will slowly ramp up to full speed

If the battery is bad then the machine should still boot, right? Only problem would be that you'd have to reset date and time and other settings after a power down / unplug. And I suspect given the age of the machine and the measured voltage that the battery is in fact bad. But probably not the reason the machine won't chime and boot.

I suspect that it's likely the logic board has failed. Guess it could be bad RAM as a second. Third would be power supply.

I can remove and reseat the RAM. Don't have a Mac G5 power supply (don't think any standard PC ATX style power supply will swap in, will it?)

Just want to be sure there's not some simple fix before I price out a logic board, which will probably result in it's owner just buying a new machine. Which is fine, as long as this machine is truly dead.



Ryy
Aug 23, 2011, 08:43 PM
The battery sounded suspect to me at first....

Did you/the user ever get the mac face folder icon with the question mark on it?

I do recall one issue I had replacing some ram in my PM G5 before. It did the same exact thing you have mentioned here. It would also have a red light that would illuminate when the bad stick of ram was still plugged in. I would check all the sticks of ram for sure.

InfoTime
Aug 23, 2011, 10:36 PM
Right now there is nothing coming up on the display. Not sure if he ever saw the folder icon with question mark in the past.

I did pick up a battery today, gonna try that tonight.

I think I recall seeing a red light. I'll pay close attention to that.

mskemp
Jul 24, 2013, 10:58 AM
After searching the internet for days I did finally try what I thought was an unlikely cause to this problem -- I changed out the video card. This solved the problem.

My specific problem was that when I pressed the power button the light was lit (no red diagnostic lights on the logic board) but after a brief spinning sound there was no startup chime and there was silence until the fans started up full blast. I had been using the computer and it suddenly turned itself off and I was never able to restart it until I replaced the video card.

If you want to test to see if this might be your problem -- before you spend money on a video card -- take the video card out of your machine and press the startup button. If you get the normal powering up sounds with normal fan noise it is likely the video card.

I had read this solution in one or more posts to this issue, but I couldn't see how that would work so passed over trying it in favor of other possible causes. I am posting this so others will take note that this is good advice even if it seems unlikely.

Good luck!

eyoungren
Jul 24, 2013, 11:34 AM
I had your exact same issue a couple of months ago. I went down the logicboard rabbit trail on this and swapped it out for around $50 on eBay.

In my case, although the symptoms are exactly the same, it was the logicboard. I have the exact same video card that was used previously plugged in, so it could not be the video card.

Nice to know though for future reference.

mmpproduction
Dec 14, 2013, 11:04 PM
I have a power Mac g5 quad core, everything work, it shime an all, but no video, can anyone help me with this problem.