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by Adam C. Engst <ace@tidbits.com>
Back in February, Apple quietly started a program to
replace the noisy fans in the Power Mac G4 (Mirrored Drive Doors). For
$20 shipping and handling, Apple will ship you a new power supply and
fan along with installation instructions. The program runs through 30-Jun-03,
so there's still time to order if you haven't yet done so.|
<http://db.tidbits.com/getbits.acgi?tbart=07081><http://depot.info.apple.com/?program=acoustic>
I received my replacement power supply several weeks ago, but I didn't
find the time to install it in my dual-processor 1 GHz Power Mac G4
until recently. Since installation involves removing numerous cables
and drive carriers as well as the actual fan and power supply, I wanted
to make sure I could afford some downtime if I screwed something up.
Luckily, I didn't, and I now have a quieter Mac.
Installation Process
Apple's instructions are detailed and accurate, though the photos are
a bit fuzzy. The photos in the PDF version that you can download from
the page linked above are higher quality, and you might find it worthwhile
to download and print them on a color printer, if available. The entire
installation process took me about an hour. I'm comfortable taking Macs
apart, but I was working methodically. An expert repair person could
probably do it in 20 minutes; if you've never opened a Mac before, it
probably makes more sense to pay a dealer to install the new power supply
for you. Overall, the instructions worked well, and I had no significant
troubles, although convincing the new power supply to slot into the
tabs in the case took several tries. The instructions aren't kidding
about needing a Phillips screwdriver with a magnetized tip; my normal
Wiha screwdrivers lack magnetized tips, and removing and reinstalling
the screw that secures the back hard drive carrier would have been extremely
tricky if I hadn't found another screwdriver with a magnetized tip.
<http://www.wihatools.com/>
Speaking of screws, that's the one place the instructions fall down
completely. They do fine at telling you which screws to remove, but
they're silent about when to reinstall those screws until the very end,
when they remind you to check that all the screws you removed were in
fact reinstalled. As long as you keep the various screws separate, and
refer back to the disassembly steps, though, it's easy to figure out
when to replace which screws.
Quieter, Less Powerful
The new power supply is rated at only 360 watts, compared to 400 watts
for the original. Apple says that won't make any difference. Similarly,
the new fan appears to have slightly different specs. More to the point,
is it quieter? Yes, though it's certainly not silent. I looked into
buying a sound meter from Radio Shack, but theirs went down only to
50 dB, and I wasn't sure if that would be low enough. So, lacking a
real sound meter, I figured out a different method of testing. My iBook
has an built-in microphone, and the Mac OS X Sound preferences pane's
Input tab has an Input level display of 15 "lozenges" that
look almost exactly like those answer bubbles you have to fill in with
a #2 pencil on standardized test forms.
By maxing out the Input volume setting (thus increasing the sensitivity
of the iBook's internal microphone to the maximum), I was able to determine
that the original power supply generally registered 6 lozenges, occasionally
dipping to 5. I took that reading right next to the machine; I also
took a reading at where my head is normally located several feet from
the machine. That second reading registered 5 lozenges, with frequent
dips to 4 and occasional dips to 3. After performing the power supply
transplant and turning the Mac on again, I was pleased to note that
the noise level was noticeably lower. Performing the same tests with
the iBook revealed initial readings of 3 to 4 lozenges right next to
the Mac and 2 to 4 lozenges at head level, with 3 lozenges being the
most common reading. There's no question these results are highly unscientific,
since the precision of the Sound preferences pane's Input level display
is sorely lacking. I also wasn't able to control for the temperature
of the room, and since the fans are variable-speed, their noise will
undoubtedly change as they increase speed to deal with higher temperatures.
My main complaint is that the new noise of the power supply isn't entirely
even. At a specific fan speed, there's a slight burbling, and I find
that burbling more distracting than the previous noise, which was louder,
but even. In an attempt to isolate the burbling, I opened the Power
Mac while it was still running (which Apple recommends you don't do).
That messed up the carefully designed airflow, and caused the fans to
increase speed - and noise - significantly. I wasn't able to locate
the culprit, and a few minutes after I closed the case, the speed and
noise returned to what has seemed like normal so far. After a few weeks,
I became more accustomed to the new noises, and the burbling doesn't
bother me as much now.
Worthwhile?
If you have a covered Power Mac G4 (Mirrored Drive Doors), should you
spend the $20 on the power supply replacement? I'd say yes, since the
only downside is the minimal cost and the slight risk of damaging your
Mac if you're careless while disassembling it. If, for whatever reason,
you don't like the sound of the new power supply, you can always reinstall
the old one. Although we initially reported that Apple would provide
an airbill to return the old power supply and fan, and the program is
called an "exchange," I received no such airbill in my package,
and there are no instructions about how to return the old power supply
in the box. There is, in fact, a single sheet of paper that says, "The
parts you have replaced as part of this exchange program should be disposed
of in accordance with local laws." If I remember my classical education,
trying to figure out your local laws with regard to the disposal of
power supplies is in fact one of the labors of Hercules. So I'm keeping
my old power supply, just in case; if you feel the need to get rid of
yours, try giving it to whatever local computer recycling center you
may have.
This Power Mac G4 is still the noisiest thing in my office, and I think
it's still noisier than the 450 MHz Power Mac G4 it replaced, but it's
better than before. Audio and video professionals who need silence will
still likely want to isolate the Mac in another room or in a soundproof
enclosure. Most everyone else will probably be happy that the new power
supply and fan are indeed quieter, even though this replacement won't
eliminate jealousy over the silence of the fan-less Power Mac G4 Cube
and older iMacs.
Reprinted
with permission from TidBITS#684/16-Jun-03. TidBITS has offered more
than ten years of thoughtful commentary on Macintosh and Internet topics.
For free email subscriptions and access to the entire TidBITS archive,
visit www.tidbits.com.
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