Redlining fans on PowerMac G5

E

ericmurphy

Registered
This has happened three times so far in the past week, and I'm thinking it's a hardware problem somewhere. Here are the symptoms:

An idle (but not sleeping) PowerMac G5 locks up completely (won't even return a ping), and the fans spin up until they're running full-blast. The only thing I can do is power it down by holding the power switch in for a few seconds. It restarts normally, and then a few days later the same thing happens. Nothing of note seems to show up in any of the logs, and I can't decypher what it's sending to Apple when it starts back up. Has anyone else experienced anything like this?

The Machine:

Late 2004 PM G5 dual 2GHz
3 Gig RAM
250 Gig HD
 
Yep. My G5 2.7 just started something similar. The fans would really wail, and the computer would sometimes do an uncommanded shutdown. Today it will not power up properly. The light on the power button will not stay lighted unless you hold it in, and yet when it's released the machine sometimes, will seem to begin power-up, but nothing appears on the monitor. If power remains on the machine, though the start button isn't lighted, the fan slowly comes up to full speed and stays there.

Looks like a trip to the G5 hospital is in order.
 
You could try the following whihch has worked for me in the past with a similar problem.

Goto System Preferences > Energy Saver click on the options tab and make sure the processor performance is set to highest. If it is not change it and quit system preferences. Restart the Mac and fingers croessed the fans should behave normally.
 
Black screen...no boot...no preferences. Nada. Can't even open the DVD tray to insert the OSX disk.

I believe I may be hosed.
 
Used the compressor and tried removing any dust. Noted what appeared to be residue in right-rear corner of machine, under the G5 processors...looked like it was the result of moisture causing dust to cake up, or maybe even electrolysis...no evidence of actual water. Machine started again, however, fan ran continually, spooling up a bit when processor demands were made. Shutoff machine and could hear fans running softly, but they were running. Showed no signs of stopping. Had to pull the plug to stop them.

I'm guessing that maybe the water-cooling is not functioning properly, which is requiring the fans to operate beyond their design capability. Any guesses?

By the way, what sat service are you using? I'm on SkyVista, and it leaves much to be desired...especially for the price.

Thanks again, Pish
 
hi
my G5 has encountered exctly the same symtoms you both have described and now it won't start. the power light goes on only as long as i hold in the button. What was you're final outcome? repair? and / or what was repaired - thanks - it will help bme decide what to do next.
Steve
 
It's only one guy with the problem, until you spoke up. No resolution yet on the problem. I'll post a solution when I get it. Unfortunately, the G5 is out of warranty by 3 months, and I don't have AppleCare. If you're warranteed, I'd suggest getting it to Apple post-haste.

Pish
 
Well, here's the scoop on my G5 and its boot/power problem. I took the machine to the Apple Store. They tore into it and found a coolant leak. They'd never seen one before.

Now they tell me I need a new power supply unit which they assume was damaged by the leak, a new pair of 2.7ghz CPUs because the cooling system is intergral to them, and probably a new logic board. Total cost? Nearly $2K. 3 months out of warranty, with an obvious long-term defect that was the root cause of the problem. So, I hope your problem isn't the same.

Kind of hard to throw away a $3K computer that is only 15 months old, but there's obviously no point in fixing it for that kind of number.

Anyone know of endemic problems with the cooling system on these machines? It's hard to believe that this is a singular event.

Thanks all,

Pish
 
and thus the tech worlds short-lived infatuation with liquid cooling systems comes back on itself.

it is a positive thought that the emphasis on new processor architecture is to prevent the need for abstract cooling systems by addressing the problem, not the symptom.

my sympathies go to you!
 
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