Fan wires are soldered to the psu board. Should I buy the new fan and cut
old wires and solder new fan wires.
Difficult but most elegant way-
Pull whole PSU board out, remove the PSU fan wires and
solder in a pin header. If spacing of pins makes that
impossible then solder new fan leads directly to PCB.
Of course with the pin header you also need a fan having
compatible pin socket.
Easier way - snip the fan leads close to the body of the old
fan. Strip insulation off of them, and the new fan leads,
slip some heatshink tubing over the leads towards the base
of the wires (away from heat while soldering), solder the
wires, slip the heatshrink tubing over the solder joints and
heat to shrink-seal the connection.
Does the voltige on all fan is the same?
The most common "PC" fan voltage is 12V. The most common PC
PSU fan voltage is also 12V. It is common for misc non-PC
fans to come in other voltages, and rarer but not
theoretically impossible for a PSU fan to be other than
12V... though offhand I don't recall ever seeing a PC PSU
fan that wasn't 12V.
In other words, read the fan label, it should state voltage.
Otherwise it is reasonable to gamble and assume the PSU fan
was 12V and needs another 12V fan for replacement.
Also signficant is the fan speed. If you can find the spec
sheet for the original fan online you may have some idea,
but some fans are OEM runs and the speed might vary from a
generic fan family spec sheet's listings. Compare the fan
amperage on the fan label to the spec sheet as there is
direct correlation in amperage and speed among same size and
voltage fans. For similar noise levels and cooling, choose
a replacement fan with similar amperage.
Avoid questionable quality sleeve-bearing (or single
ball-bearing plus sleeve bearing) fans for a PSU exhaust as
they have short lifespans in such uses unless they have a
very good bearing and lube system- which most unknown or
low-end fans don't. Dual ball bearing name-brand (fan
manufacturer brand, not fan relabeler-for-PC-products) fans
are the best choice for this use.