'Unreal' Mirror Drive Door Tower Cooling Mod
By: Chris M.
Posted: June 4th, 2004
Updated June 7th, 2004 for comments/photos on Adj. PSU Fans)
Hey Mike, first of all thanx a lot for your site. Since I started fiddling around on my first beige G3, I regularly checked your site for helping tips. I successfully overclocked every G3 I owned, I converted my overclocked G4 sawtooth into an ATX-case, helped the quicksilver to shut up and now tried something new for once:
I recently bought a used G4 1 GHz Dual MDD, and, as everyone knows, these beasts are loud. by chance I got an original silent kit for a few francs (there's still no euro in switzerland :-) and was quite satisfied with noiselevel after the swap.
But I noticed the upper half of the case heating up quite a bit. Even the PCI-bezels felt really hot. There is no exhaust for the hot air except through the power supply, which starts to run quite hot after half an hour. A pci slot cooler helps evacuating the hot air, but adds some more noise and is not that efficient due to the small diameter.
I run 3 harddrives, normally 4 pci-cards and an additional DVD drive (due to region code things), so maybe all these devices help to heat the mac up.
So I simply decided to pump some fresh air into the powersupply and the
pci-compartment by removing the little loudspeaker, drilling up the hole and placing an ordinary case fan (coolermaster with heatsensor) there. it runs silently, the air leaving the back of the powersupply doesnt feel as hot as before, I now also removed the pci-slot-cooler (i want to use all of my 4 pci-cards).
Finished Front View
i didn't put the plastic covers from the backside of the machine on again. (ok, to tell the truth, I had made some experiments to colorize the surface - and I messed it up :-) Maybe the airflow out of the case might be a little better now.
The result is great. The cpu-temperature dropped from 58.3 celsius (that's where my fan kicked in every few minutes) to 54.4 degrees. The temperature near the powersupply dropped even more. Touching the pci-bezels does not feel hot anymore...
The 12cm case fan runs constantly at lowest speed and the newly installed 8cm fan is barely audible. Loudest things now are the powersupply-fans (remember, this is the apple silent kit). All in all the G4 is quiet enough for me, I just hear a whisper under my desk and do not have to worry about heat anymore.
The whole modification took me about 4 hours.
The most dangerous thing while doing this mod are the iron shavings. One tiny little particle of iron can kill your logicboard (if it shorts across two traces). So take the time to dismantle the whole machine and clean everything thoroughly after widening the original speaker hole,
then the rest will be a piece of cake :-)
And it tastes good.
(he later sent an update with comments/photos on replacement PSU Fans)
After running the G4 during 36 hours nonstop, the temp rose to max. 55.6 degrees while i was shooting my way through unreal worlds :-)
since the power supply remained fairly cool during all this time, I chose to go a little further by digging out the old (loud) samsung-PSU, exchanging its noisy delta-fans with some titans I had laying around and reduce their speed with a little fan-regulator.
(reader FYI - in August 2002 (before the Apple PS/Fan swap program)
a MDD owner sent an article on replacing the Fans in the original MDD Pwr Supply.)
After swapping the apple-silenced-PSU with my titan-version, I noticed the G4 is now a little quieter. (I dont believe it would be good idea to reduce the fan speed without having enough fresh air availlible near the PSU)
Little effort, little gain. but ok; i can sell the apple silent kit to someone who is really in need.More Photos
Loudest thing now is the case fan (papst 4212, i think), but its quite powerful in moving much air at low speed, so i will keep it. its noise-level is followed tightly by the 3 harddrives anyway.
i think, making the G4 quieter would start to become an expensive thing.
P.S. Notice the little dial looking out the top of the PSU cover?
After and Before
Speaker Hole Mod
Rear View of Fan
Front Cover Mod
Replacement PSU Fans/Fan Mate
PSU w/Adjustable Speed Fans Installed
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