iMac G5 Noise and Sleep Issues

[Maniamac]

I'm aware that fan noise and power supply issues are fairly common on the iMac G5. My Rev A model, however, has been problem-free... until now. Recently I've noticed a high-pitched whine of sorts emitting from the top-center or -right of the computer. The sound was definitely not there before. I find it hard to characterize the whine with great specificity; it almost sounds like a loud electronic hiss. If you're at all familiar with the infamous MacBook idle processor whine, you'll have a good idea, only this sound is louder than that. Also, the computer will no longer stay asleep; resetting the SMU and the PRAM did not help.

I should note also that,

1. The computer passes the Apple Hardware Test.
2. The whine disappears when the computer is asleep or off.
3. When the computer and display are awake, it is constant in pitch. Processor-intensive tasks do NOT make the whine louder.
4. The pitch of the whine changes in the seconds immediately before the computer sleeps and after it wakes.
5. During the start-up sequences, the display dims and brightens. This is particularly noticeable on the white screen with the gray Apple logo. I would suspect the power supply, BUT....
6. Lowering the brightness of the screen does not reduce volume of the whine.

Can anyone hazard a guess as to what problem my iMac may have? I hope it's nothing too expensive, especially if it renders my computer a ticking time bomb....

In any case, I appreciate any help you all might offer!

 

[wrldwzrd89]

I'm aware that fan noise and power supply issues are fairly common on the iMac G5. My Rev A model, however, has been problem-free... until now. Recently I've noticed a high-pitched whine of sorts emitting from the top-center or -right of the computer. The sound was definitely not there before. I find it hard to characterize the whine with great specificity; it almost sounds like a loud electronic hiss. If you're at all familiar with the infamous MacBook idle processor whine, you'll have a good idea, only this sound is louder than that. Also, the computer will no longer stay asleep; resetting the SMU and the PRAM did not help.

I should note also that,

1. The computer passes the Apple Hardware Test.
2. The whine disappears when the computer is asleep or off.
3. When the computer and display are awake, it is constant in pitch. Processor-intensive tasks do NOT make the whine louder.
4. The pitch of the whine changes in the seconds immediately before the computer sleeps and after it wakes.
5. During the start-up sequences, the display dims and brightens. This is particularly noticeable on the white screen with the gray Apple logo. I would suspect the power supply, BUT....
6. Lowering the brightness of the screen does not reduce volume of the whine.

Can anyone hazard a guess as to what problem my iMac may have? I hope it's nothing too expensive, especially if it renders my computer a ticking time bomb....

In any case, I appreciate any help you all might offer!

I have an iMac G5 Rev. C, and I have issue #5 that you mentioned but it doesn't concern me too much. As for the whine, I'm not sure... my own iMac definitely has fan noise issues, but that sounds minor compared to what you're experiencing.

 

[Soulwar]

See if your iMac is covered under the repair program.
http://docs.info.apple.com/article.html?artnum=302181

 

[velocityg4]

I could be wrong but it sound to be like it could be your powersupply failing. Recently on my fathers PC it had a high pitched static whine caused by a failing capacitor on his powersupply. Once I replaced the powersupply everything was fine.

Are you getting static through external speakers?

You could remove the iMacs back plate and rest it face down on a clean cotton towel, to protect the screen, then turn it on again to better locate the noise. I used a stethoscope to isolate the powersupply from the powersupplies fans.

 

[Maniamac]

I have an iMac G5 Rev. C, and I have issue #5 that you mentioned but it doesn't concern me too much. As for the whine, I'm not sure... my own iMac definitely has fan noise issues, but that sounds minor compared to what you're experiencing.

Thanks for the reply. I've pretty much gotten used to the fan noise. The iMac G5s are surely not the whisper-quiet machines they were advertised to be. It's this static whine that concerns me.

See if your iMac is covered under the repair program.
http://docs.info.apple.com/article.html?artnum=302181

Thanks, Soulwar. I'm aware of the program. Unfortunately, it seems the program only covers repairs within three years of the original date of purchase.

I could be wrong but it sound to be like it could be your powersupply failing. Recently on my fathers PC it had a high pitched static whine caused by a failing capacitor on his powersupply. Once I replaced the powersupply everything was fine.

Are you getting static through external speakers?

You could remove the iMacs back plate and rest it face down on a clean cotton towel, to protect the screen, then turn it on again to better locate the noise. I used a stethoscope to isolate the powersupply from the powersupplies fans.

I'm thinking it is indeed the power supply. Today my iMac is periodically shutting down instead of sleeping the display. That sounds like a power supply issue, does it not?

Might be time to retire the old feller!

Thanks, everyone.

 

[velocityg4]

Well if it is the power supply and you are set on getting rid of it you could either get a few hundred selling it as for parts only computer on ebay. Or get a replacement PSU for $100 on ebay then sell it.