Re: Power Supply fan

On Sun, 14 Dec 2008 12:31:53 -0500, NickySantoro
<NickySantoro@optonline.net> wrote:

>The PSU in my comp has 2 fans, one on each end. The inner most fan has
>begun making some noise which goes away after a couple of minutes.
>I've thoroughly cleaned it but the noise persists and I think I need
>to replace the fan. How would I determine what size fan to order?
>TIA

Take the fan out, pull the plug off the bearing, and put a
couple drops of heavyweight oil in it while holding it
horizontally. Gently rotate the blades a few times to work
the oil into the bearing, then put it all back together.

While you're in there lubing it, take note of whether this
fan has a connector on the end of it's wires or is soldered
to the PCB. If it's a connector you might be able to find a
fan with the same connector on it, saving you from having to
solder the new fan's leads to the old ones (and finish it
off by having pieces of shrink-fit tubing on that seal it.

Measure the fan for replacement by noting the width of the
frame in millimeters, as Grinder noted it is typically 80mm,
a 92mm fan would be taller than the PSU itself is since it's
on the back (case-front facing side) instead of on the
bottom of the PSU. I take that back, rarely an OEM PSU will
have a 92mm fan on the front or back but I've never seen one
of these extra-height non-ATX form factor PSU that had two
fans instead of only one in the rear.

So it's almost certain to be 80mm diameter but might not be
the most common 25mm /(often called 1") thickness, to save
space some PSU will use a 20mm or 15mm thick fan.

You don't mention your system's major parts nor the PSU
model, but most psu get along fine with only the rear fan,
not having a 2nd fan at all. Typically a 2nd fan is added
to try and get more wattage out of a PSU the cheapest way
possible but if your system doesn't need that last hundred
watts from the PSU, you may not need that fan at all (could
just put a fan grill over the area if it's completely open
and wires might too easily get inside), or you could select
a fan with lower current rating (typical of one having lower
RPM), to reduce noise and extend it's lifespan.

Lastly the original fan is probably failing prematurely
because it's a low quality sleeve bearing fan. If you
choose a major manufacturer's dual ball bearing fan you may
avoid having to ever replace it again, or if you prefer
sleeve bearings then look at the highest quality ones like
those from Papst or Panaflo, assuming either makes the size
you need.

If after oiling it, it completely resolves the noise, you
might find you never have to replace it, only relubing it
again every year or so... depends a bit on how worn it is at
this point, how low a quality fan, high fast it spins.

Note also that if the rear fan is a similar quality sleeve
bearing model, it might be good to go ahead and lube that
one too, to keep it from wearing down the bearing as happens
when it runs out of lube. If it is instead a dual ball
bearing fan, do not try to lube it. If it only claims "ball
bearing" without being DUAL ball bearing, it may have one
ball and one sleeve bearing in which case it ought to be
lubed, just put a small drop in so there's less chance of
excess oil getting into the second, ball bearing portion.