The process is risky due to the voltages involved and not for the casual user.
This information applies to a standard ATX power supply.
Almost all modern consumer power supplies are ATX power supplies.
Before you begin, readthese important PC repair safety tipsbecause of the dangers involved with the process.
Manually testing a power supply involves working closely with high voltage electricity.
Don’t skip this step!
Open your machine’s case.
Unplug the power connectors fromeach and every internal gadget.
Each group of wires should terminate to one or more power connectors.
Group all the power cables and connectors together for easy testing.
This will make it as easy as possible to test the power supply connections.
Short out pins 15 and 16 on the 24-pin motherboard power connector with a small piece of wire.
Look at theATX 24-pin 12V Power Supply Pinouttable to determine the locations of these two pins.
Confirm that thepower supply voltage switchis properly set for your country.
In the US, the voltage should be set to 110V/115V.
Check theForeign Outlet Guidefor voltage parameters in other countries.
Plug the PSU into a live outlet and flip the switch on the back of the power supply.
Some power supplies don’t have a switch on the back of the unit.
Just because the fan is running doesn’t mean your power supply is supplying power to your devices properly.
You’ll need to continue testing to confirm that.
Turn on your multimeter and turn the dial to the VDC (Volts DC) setting.
If the multimeter you’re using doesn’t have an auto-ranging feature, set the range to 10.00V.
I recommend testing every pin on the 24-pin connector that carries a voltage.
This will confirm that each line is supplying the proper voltage and that each pin is properly terminated.
it’s possible for you to referencepower supply voltage tolerancesfor a list of proper ranges for each voltage.
Are any voltages outside the approved tolerance?
If yes, replace the power supply.
If all voltages are within tolerance, your power supply isn’t defective.
If you’re not interested in testing further, skip to Step 15.
Turn off the switch on the back of the power supply and unplug it from the wall.
Reconnect all your internal devices to power.
The biggest mistake made at this point is forgetting to plug everything back in.
your gear or motherboard manual should explain how to do this.
Did your power supply pass your tests, but your machine still isn’t turning on properly?
There are several reasons a computer won’t start other than a bad power supply.
See ourHow to Fix a Computer That Won’t Turn Onguide for more help.
