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

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

Reply to
AZ Nomad

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

Reply to
junebug

Several internet vendors stock PC power supply testers. MCM Electronics has a couple at

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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.
Reply to
DaveM

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.

Reply to
AZ Nomad

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

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mistermaniac
Reply to
mistermaniac

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

Bart Bervoets

Reply to
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.

Reply to
AZ Nomad

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
Reply to
jdgill

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Reply to
Ray L. Volts

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.

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do_not_spam_me

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