My fan on my power supply seems to have slowed down and the pc is getting
hotter than it should. How easy is it to test or replace the fan ?
We might have a little more to go on if you'd mentioned the
make and model of power supply, and of the fan. Some have
thermal-sensing circuit which slows down the fan, so if the
PSU itself wasn't very hot but the rest of the system relied
on the PSU as the sole chassis ventilation (which is
generally not recommended these days due to increased
component heat production compared to older systems) then of
course everything else would be getting hotter. Yet, it
doesn't explain a change from prior working state which (by
ommision) we migth assume it was cool enough previously.
So IF the fan is low-quality with a sleeve bearing you might
try adding a drop or two of thick oil to the bearing. If
the fan exhaust has a stamped-in metal grill opposed to a
chrome wire grill, you'll probably have to disassemble the
entire power supply just to get to the bearing (behind the
sticker). It's not hard, not a "lot" of work relative to
some things but a hassle nonetheless when the power supply
could've simply used a better fan and cost $1 more.
Otherwise, typically the fan doesn't have an RPM output on a
power supply. Some do though and if yours does you could
compare the RPM to the fan manufacturer's spec for that fan
model, yet you also would need take voltage reading to
determine the voltage, since a control circuit lowering the
voltage will certainly lower the fan RPM on almost any
PSU/fan.
As for swapping it with a different fan, certainly it's
possible, you'll need determine the extent of the job and
what you're willing to do, as some have different plug-on
connectors than others, usually not the type that has a
3-pin motherboard connector but rather a 2-pin (which
"might" be trimmed down to fit with a sharp knife) that
might also need the wire positions, polarity, reversed, OR
it could be a smaller pin-header in the power supply which
needs a different fan connector. Since you asked the basic
question about the fan I'll presume you're not accustomed to
dealing with these internal parts, but there are a lot of
alternatives too for someone willing to go further, like
removing the entire pin-header and soldering wires directly
to the circuit board, or putting a different connector on
the fan leads.
Other alternatives might be splicing a new fan's leads to
the old fan leads, perhaps the easiest when the new fan
isn't compatible but if you go that route make certain the
wires are secure, generally soldering then heatshrinking
them is preferred over just twisting, crimp-splicing and/or
wrapping with electrical tape. A PSU can get rather warm
inside and electrical tape may not be sufficient.
Opening the power supply and noting the fan connector and
circuit board plug (or direct-solder alternative) is a good
first step, and while the power supply is open go ahead and
try adding a couple of drops of oil to the fan bearing.
Perhaps the lubed fan will keep working well or perhaps it
won't but you then have a good idea of what will be
necessary to replace it.
Just make sure you unplug the power supply from AC for a few
minutes before opening it. If it's an old or cheap power
supply it might be best to just replace the whole thing. If
only replacing the fan choose a decent name-brand with
similar RPM, or failing the ability to determine RPM of the
original, choose one with similar amperage rating.
