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PowerMac G4 MDD

macrumors 68000
Original poster
Jul 13, 2014
1,900
277
Hi, everyone! Dropping by again to seek out some help from the good ol' PPC community.

I know that this is regarding an Intel machine, but it's an issue general enough that it isn't necessarily Intel-iMac-specific. I already asked on the Intel iMac forum, but users over here are much nicer and willing to help out. It's a struggle getting answers on other forums!

Several months ago, I got a high-end, 24" iMac (2008 model) that had suffered from a GPU failure. Just this weekend, I decided to part it out; however, while I was at it, I figured I'd give the GPU 'oven' method a try, since I had nothing to lose and was taking the machine apart anyway. So I modified the method and stuck the GPU underneath a HOT-HOT-HOT halogen lamp... and it fixed it right up!

So far, it has been running like a champ. However, I woke it up yesterday and suddenly heard this odd humming/buzzing coming from the machine - sort of like a lower-pitched version of the humming you might hear from a cheap LCD monitor whose power supply(?) isn't at its healthiest. I researched a bit and found that this issue is somewhat common; it's, I guess, related to the power supply. [Take note that the noise stops when the screen itself is asleep, or when I turn the brightness up to 100%. Anything below 100% and the noise is there. My eyes are sensitive to bright light, so adjusting it up all the way is no proper fix for me.]

The bottom line is the following: I don't want to pay the $150-ish it takes for a new PSU (and I envy those who have the 20" models, as their PSUs can be had for about $18). Is it possible to service the existing power supply (should it be the issue here)? Maybe there are some coils I can tweak or something? I'd be willing to either fix it with or without small parts, but buying an entirely new PSU is out of the question for me.

I am open to any suggestions. Hopefully this is something I can fix myself, and hopefully this doesn't mean that the PSU could give out sooner or later. THEN I'd be in trouble. Thanks in advance for any answers!

-MDD
 
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