How to determine temp of PSU?

  • Thread starter Thread starter Sherry
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Sherry

Hi,

I'm planning on quieting my power supply by replacing the fan, but I don't
know how to tell what CFM my supply really needs, since I can't watch it's
temperature like I can with the CPU/case/chipset/video/etc..

Anyone know how to do this?

-Sherry
 
Hi,

I'm planning on quieting my power supply by replacing the fan, but I don't
know how to tell what CFM my supply really needs, since I can't watch it's
temperature like I can with the CPU/case/chipset/video/etc..

Anyone know how to do this?

-Sherry
Click to expand...

You have to install a temperatire sensor inside the supply (regular
cautions apply to messing with the insides of a power supply), or
measure the temperature of outgoing air.
 
You have to install a temperatire sensor inside the supply (regular
cautions apply to messing with the insides of a power supply), or
measure the temperature of outgoing air.
Click to expand...


The temp measured at the exhaust vent is a good measure of the
average. Measure it before you take the PSU out, and again after
you've installed a new fan. If the temp is no greater it's safe
to assume that the new fan is good enough.

If it's higher I'd get a big quiet case fan set to suck air into the
cabinet. The increased preasure will increase airflow thru the PSU,
and the rest of the case, in general. I claim no experience on how to
make quit PCs.
 
Sherry said:
I'm planning on quieting my power supply by replacing the fan,
but I don't know how to tell what CFM my supply really needs,
since I can't watch it's temperature like I can with the
CPU/case/chipset/video/etc..
Click to expand...

For the sake of safety I strongly suggest you check only the
temperatures of the power supply case and the exhaust air, neither
which in a 75F room should not exceed about 110-120F at the hottest
spots.

The best locations for measurements inside the supply are at the large
transformer and the large heatsinks (purists will say that the power
transistors and diodes on the heatsinks ar what really should be
measured, but tight packaging makes this difficult), but one of the
heatsinks is usally connected directly to a 170VDC source, even when
the computer is turned off but plugged in (can retain this voltage for
several seconds afterward). Because of high voltages it's best to use
an infrared thermometer so that readings can be made without touching
the devices, but any readings first require running the supply for
over an hour with the cover installed because with the cover removed
the air flow will be very different and make the heatsinks 50F hotter
than normal. Power semiconductors are made to withstand at least 200F
 
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