testing computer power supplies

Is it bad for a computer power supply to be switched on without a load?
I know it's possible to start the power supply, i get loads of power
supplies in
from returns but i don't want to chance blowing a mainboard up
(i could hook an old cd rom drive up to put a load on 5 and 12v but
would like to avoid clutter.)

Bart Bervoets

 

Put a bunch of power resistors in a switchbox. I used an old power
supply and kept its fan for cooling the resistors.

 

Just use an old hard drive or CD-ROM drive. That should be enough load
to get the power supply started.

 

Several internet vendors stock PC power supply testers. MCM Electronics has a
couple at
http://www.mcminone.com/category.asp?catalog_name=MCMProducts&category_name=1000143&Page=1

Cheers!!!

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Some days you're the dog, some days the hydrant.

 

That depends on the color of cables the PS maker felt like using.
You should learn where on the power connector those two leads are instead
of relying on the PS maker following a particular color scheme.

 

Just build a dummy load with a bunch of resistors or so.
If you connect green and black, an ATX power supply will switch o

 

True, the diagram is available so i can check which pin it is.

Bart Bervoets

 

I learned (at least on a 20 pin ATX), that if you have the connector
facing you with the key to the right, shorting the two pins above the
key will turn the power supply on.

If it's been more than a few months since I last did the trick, I go
to google to doublecheck.

 

Bart:
I made a load consisting of a couple of old 12V tail light bulbs with
10 watt resistors in parallel with the bulbs, so that they draw about
3 amps each. I attached a regular power supply male connector
to the wires so that I could plug it into one the the PS connector.
This test rig is mounted on a little stand so that I do not have to
worry about shorting the wires.
This way I can test the 5V and 12V lines to see if they are working
properly. I always use a DMM to check the actual voltages, but the
test rig makes it easy to see if a supply is working.
John

 

http://www.certiguide.com/apfr/cg_apfr_TestinganATXPowerSupply.htm

 

It doesn't address his question. It also says:

"Be aware that a power supply may display proper voltages
when nothing is connected to it, yet these voltages can fall

below acceptable levels when a load is applied."

This is correct, but more often, voltages will be out of tolerance not
when a load is applied but unless a load is applied.

I wouldn't rely on PC "technician" courses or guides for correct
hardware information.