Random Sleep Mode / Overheating Issue (iMac G5)

R

readjdm

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I work on a 1 1/2 year old iMac G5 -- one of the 20-inch flat-panel monitor ones -- using Tiger. The other day, I started experiencing a new problem where the computer suddenly, and without any warning, went into sleep mode. Pressing the space bar brought it back to life, but it soon went into sleep mode several more times -- each, like the first time, without being asked to do so. This happened while I was in the middle of running a full-system scan with my new anti-virus software. I closed out of any other programs and walked away at that point, to let the computer finish doing the anti-virus thing. When I came back to it in the morning, everything worked a-ok, and I was able to surf the web, print out some eleventh-hour tax returns, etc., etc., without any incident.

Later that evening, however, the random sleep mode issue came back again. I ran into it the following evening as well. In both cases, I was attempting to print stuff from such programs as Photoshop and InDesign.

From the research I've done so far, everything seems to be pointing towards a power source/energy usage issue. My assessment is that the system is simply starting to overheat. The problem is, I don't have any clue what to make of that, nor what I should do to either fix the problem or stop it from happening again. For example, I've got the widget for checking the system temperature, but what am I supposed to do with that information? What temperatures am I looking for? What's considered a "good" or "proper" system temperature? What's considered a "bad" or "problematic" one?

Also, what components of the computer cause this sort of problem, exactly? If I'm experiencing random bouts of sleep mode, does that necessarily mean those components are damaged? Is there some kind of software I need to fix them? Am I supposed to physically open the computer? Take it in for repairs? Avoid certain behaviors, such as running multiple programs at the same time (which isn't exactly ideal)?

I realize this is a long list of things to be asking all at once, but I haven't been able to find one good, solid answer to this issue, so I'm really looking for as much help as I can possibly get.

Oh, one more thing: Five minutes ago, the fan on my computer started making really loud sounds. I tried closing out of all programs to turn off the computer -- and it froze. It's now pinwheeling while the loud fan noises continue; I'm writing this from another computer, as I haven't been able to get it to shut down yet.

I'm pretty desperate for help here. Any advice you can share will be GREATLY appreciated. Thanks!
 
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I've just started experiencing, almost word for word, the exact same issues as this, with the added note that I JUST had my power source replaced, with no apparent change in heat issues.
 
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I have a 1.5 GHz PowerPC G4 512 MC DDR SDRAM MacMini... and I am having the same random sleep problem with my mini when I am watching youtube videos, using iMovie(importing and exporting and watching) and lately it's become worse and I have no idea what to do and I cannot find anybody with the problem on a mac mini... this is the closest I've seen somebody having the same problem, but with a different computer.. HELP!!!!!!!
 
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Your Mac's Specs
20", 2.4ghz iMac/4 gigs of ram + a 2.1ghz MacBook/160gb 7200 rpm Seagate HD/1 gig of ram
If you are running 10.5, download a program called SMCfancontrol. It allows you to set your fan speeds higher than default. I find apple default fan settings are to low to keep the temp down.

Could you tell us the temperatures of you CPU etc? Your computer sounds like it is just protecting itself from over heating by going to sleep (thus cutting down the number of process, thus heat).
 
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My fan is running at 5600 rpm and sounds like a freaking jet engine. That's not the problem. The problem is that even after two power supply replacements, the CPU is jumping straight to 49º and staying there, even when nothing's active.
 
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grr

Mac OS X 10.4.11.... when i turn my computer on, the temp. widget says 28degrees C. and then about ten minutes later it jumps all the way up to about 56 degrees C, and then it shuts down... it happens constantly lately just when i'm sitting here .. anytime something is moving on the screen it over heats and shuts off pretty much.. it makes me want to throw my computer out the window. wha'ts the prob, bob!!!??
 
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Your Mac's Specs
20", 2.4ghz iMac/4 gigs of ram + a 2.1ghz MacBook/160gb 7200 rpm Seagate HD/1 gig of ram
My fan is running at 5600 rpm and sounds like a freaking jet engine. That's not the problem. The problem is that even after two power supply replacements, the CPU is jumping straight to 49º and staying there, even when nothing's active.


Hardware issue then, bring it to apple. Seems like you have no other choice.
 
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Oh hey, was only seeing my HARD DRIVE temp. My CPU is running at around 75º when simply browsing the web. **** me...
 
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Hey guys!!

So, what happened to this problem? I'm still suffering, particularly since I got so mad the other night, I smashed my Mighty Mouse, along with my hand which accidentally hit a sharp edge on a paper tray. Ouch, that hurt!

Is there a solution to this issue at all?

Regards,
JagMac
One customer!
 
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loud imac

If you are running 10.5, download a program called SMCfancontrol. It allows you to set your fan speeds higher than default. I find apple default fan settings are to low to keep the temp down.

Could you tell us the temperatures of you CPU etc? Your computer sounds like it is just protecting itself from over heating by going to sleep (thus cutting down the number of process, thus heat).


I'm running 10.2.8 so can't download that program but I think that must be the problem I have with the fan - sooo loud, driving me mad....
How do I find out the temps by the way?
I don't have the problem (yet!) of the sleep mode.

I first noticed the fan noise in the summer when it was very hot (not last summer) so thought it was to do with that somehow but now it is pretty much constant and I can only work in short bursts before I have to give myself a break.
Help please
 
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I had the same issue. I ran a temp app on my imac g5 and it was running at 85 degrees plus. I reset the pram - nothing. Reset the firmware - nothing. Then I read about the air vents getting blocked and problem solved. The temp is down to 61 degrees. So thanks to whoever posted about clearing the airvents!! You're a life saver!!

My problem was the small circular airvent was blocked. You'd never know it was there unless you were looking!!:D
 
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Then I read about the air vents getting blocked and problem solved. The temp is down to 61 degrees. So thanks to whoever posted about clearing the airvents!! You're a life saver!!

My problem was the small circular airvent was blocked. You'd never know it was there unless you were looking!!:D

I was having the same random sleeping problem. I'm on my second flat screen imac (and umpteenth mac since 1994), and never knew that little intake vent was on the back, as it's aesthetically hidden behind the stem underneath the power cord. I cleaned it, and the output vent at the top, AND IT TOTALLY WORKED. THANK YOU FOR THE POST!
 
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I have a 1.5 GHz PowerPC G4 512 MC DDR SDRAM MacMini... and I am having the same random sleep problem with my mini when I am watching youtube videos, using iMovie(importing and exporting and watching) and lately it's become worse and I have no idea what to do and I cannot find anybody with the problem on a mac mini... this is the closest I've seen somebody having the same problem, but with a different computer.. HELP!!!!!!!

My daughter's G4 Mini had this problem, and I was equally flummoxed. The problem turned out to be pretty low-tech, actually -- the innards had become coated in an insulating layer of dust, and so it kept overheating and going to sleep.

I went to iFixit.com and found a great walk-through for disassembling a Mini -- I had to remove the cover and then unscrew and lift out the mass storage assembly. Then I grabbed a can of compressed air and blasted out every nook, corner and cranny. The process was a bit fiddly, but I managed just fine (and I'm no computer tech). Now, my girl's Mini is as good as new. I even torture-tested it by ripping a DVD in Handbrake -- about three hours of 100% processor load.

The iFixit walk-through is here.

Follow steps 1-9. (I didn't find it necessary to sharpen my putty knife.) After thoroughly blasting out the dust, reverse the steps to reassemble.
 

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