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Ih8reno

macrumors 65816
Original poster
Aug 10, 2012
1,383
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Recently I came into possession of a iMac G5 1.8ghz 512mb ram 160gb hdd (Powermac 8,2) Problem is it makes a whining/whistling sound when running. Anybody have any ideas on to what the problem is? Also, is this something I can repair myself?


Thanks
 
Do you hear that noise all the time, whenever power is on?

That might be fan noise (the fans are running at high speed.)
You can probably reset the power manager (known as the SMU on your iMac G5) which should get the fans working normally again. Do that by
1. unplugging all cables from the computer, including the power cord.
2. Wait 10 seconds.
3. Plug in the power cord while simultaneously pressing and holding the power button on the back of the computer.
4. Let go of the power button.
5. Press the power button once more to start up your iMac G5. (plug in whatever other cables you use)

If the noise does NOT occur until your iMac is in use for several minutes, then you slowly hear more noise - it might just b e heating up (because the cooling passages are partly plugged) and the fans have to work harder for cooling (and you hear a lot of noise.
 
I had one similar to this (17" 1.6GHz) that would do that same sound. For me it was the bottom fan that cools the CPU and it would always get loud. What I would do to keep it a bit quieter would be go to Sys Pref and under Energy Saver there may be a performance tab and set it from Performance to Power Saver/minimal. This made it quieter but I did take a hit on performance.

One day I did take it all apart and even with cleaned out fans and new thermal paste it still liked to whistle!
 
So far I took off the back panel and cleaned out as much dust as I could.the fans for sure are going slower as I installed istatpro and it shows lower rpm. The sound isn't as bothersome anymore. I will try the powersaver mode and see if it helps any more.
 
So far I took off the back panel and cleaned out as much dust as I could.the fans for sure are going slower as I installed istatpro and it shows lower rpm. The sound isn't as bothersome anymore. I will try the powersaver mode and see if it helps any more.

Your name stand for "I Hate Reno?" Hey, me too! Actually I'm an hour off from there and everything in my town is like nothing and if I need the Apple store the Reno one is the closest to me. Hey, at least Susanville has a walmart lol
 
Actually has nothing to do with Reno the place, it's more complicate then that.
 
I would have thought its fan noise. An iMac G5 would have accumulated quite a lot of dust over the years, so that would be my best guess.
 
Most of the noise is gone and did the reset. Still a slight whistle but this is something I can live with.
 
Removing the dust might not be enough. The easy way - if you don't need full processing power you can set Power Settings to "Reduced" mode and it will be silent as ninja :p. My iMac G5 can play YouView/MacTube 480p videos in this mode without fan noise.

Hard way: for the best results it would require applying fresh thermal paste and tinkering with heatsink.

https://discussions.apple.com/message/9763567?messageID=9763567#9763567?messageID=9763567

see spirochete posts.
 
Update

Changed the ram and bumped it up to a max of 2gb. Lowered the performance settings and so far no more whistling! Been using it on osx 10.5.8 and playing old school video games via emulators.
 
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