Narcoleptic G5s (#2): Bad hardware?; potential workarounds
We continue to cover an issue where some G5s fall asleep right after waking up.
Bad hardware? A new thread regarding a similar issue has popped up on the Apple Discussion boards. In this case, G5s are falling asleep during normal usage, apparently due to a thermal management issue. Users experiencing the issue report the string:
"PowerMac7,3 Thermal Manager: Thermal Runaway Detected: System Will Sleep"
appearing in the Mac OS X console.
One poster writes " Dual 2.5 just came back. Appears problem was with one processor thinking it was overheating even though it wasn't, and the fans go nuts in response. Had the dual processor unit changed and last I heard he said it was running ok. I think that the problems are due to a rogue faulty batch of G5 processors slipping by testing/QA at the IBM factory."
MacFixIt reader Clark Jackson reports a strikingly similar situation "I had a dual G5 2.0 that was falling asleep frequently without cause. I finally tracked the problem down to a bad CPU. Running the hardware tests indicated the problem; boot from the CD (or DVD?) that came with the computer and run the hardware tests. One indication I had that the CPU was bad was that prior to failure one of the fans was running much more that it should have.
"Ultimately I replaced 3 burned up CPU?s; it was my mother board that was causing my CPU?s to fail. It must have been some kind of voltage regulation issue because after replacing the mother board the problem (of burning up CPU?s) went away."
Potential workaroundsResourcesWaiting for a full wake-up In many cases, as previously reported, G5s experiencing this problem will wake from sleep momentarily only to drift away in a matter of seconds. MacFixIt reader Marvin Sable reports that in his case, simply waiting for the machine to fully wake up before introducing any mouse or keyboard activity, caused the problem not to occur.
"I experienced the G5 suddenly and quickly returning to sleep mode after trying to wake it. I discovered that if I just hit a key and "waited" till it woke completely before trying to mouse or type, that it did not go back to sleep mode uninvited. "
Resetting PRAM A handful of readers have reported that resetting their G5's PRAM, as described in Knowledge Base article #2238, resolved the issue.
In order to reset PRAM, shut down the computer, turn it back on, then immediately hold down the Command, Option, P, and R keys until the computer restarts and you hear the startup sound for the second time.
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Oh no! There's typo's everywhere! What sahll we do?
G5's?
but I won't use it again.
This morning for the first time my G5 wouldn't wake properly from sleep. I.e.,
it would wake up, then I would enter my password (which is valid) but it
would go back to sleep.
After a couple of failures like this, I switched to a different account. That
worked fine. Then I switched back to the original account that had been in
use while asleep, and this time I could log in fine.
So fast user switching might be a work-around, or this might be a
coincidence.
My connected iPod clicked every few minutes as if it was being connected or
the drive activated for first time.
I of course then did a complete shutdown and booted the thing.
ok i use a g3 350 mhz i have 1 gb of ram but there 3 gb of vm memory use
processor replacement today. My system log showed
several instances of "thermal runaway" I certainly hope
it's not a motherboard problem as I waited 2 months for
it to ship, still waiting on the Nvidia card to ship and
have wasted countless hours of productivity talking to
(unintelligible) Indian call center operators only to
diagnosing the problem from your thread. I really have
lost faith in this product and company through out this
ordeal. What's the chance that I got a lemon and that
this problem is only the beginning?
- by lharvey October 4, 2004 12:35 PM PDT
- I have a brand new dual 2.5 G5 (delivered 23 Sept). It suffers from the
- Like this Reply to this comment
-
(9 Comments)narcoleptic symptoms and the system log show the 'thermal runaway'
message. I have been monitoring both the temperature (with Temperature
Monitor) and the CPU load (with Activity Monitor). Normally the CPU temps
hover around 50 deg C. The narcoleptic attach is preceeded by a sudden
increase in CPU temperature and when it gets into the 80's the computer goes
to sleep. But there is no corresponding change in CPU load: just loafing
along. I have reset PRAM but no effect. Has Apple responded to the problem?
I don't want to destroy a CPU and don't want to send the computer off for a
week or two. Any suggestions?