test psu, unplug motherboard power 20/24 pin connector, use a paper clip wrapped in electrical tape (5 volts) to jump green wire and a black wire this should turn on the psu, if it doesn't come on it's dead, if it does you can use a voltmeter to test power.. this is not for pre p4 dell comptuers they use a proprietary connector
Connect the negative probe on the multimeter (black) to any ground wired pin and connect the positive probe (red) to the first power line you want to test. The 24 pin main power connector has +3.3 VDC, +5 VDC, -5 VDC (optional), +12 VDC, and -12 VDC lines across multiple pins.
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.
don't forget to reset the cmos when you reconnect the power, there is a clear cmos jumper on almost all desktops, it will be a jumper on 2 pins with one open pin, just move jumper to open pin +middle pin then back.
if comp still doesn't come on, could be cpu or mb
Connect the negative probe on the multimeter (black) to any ground wired pin and connect the positive probe (red) to the first power line you want to test. The 24 pin main power connector has +3.3 VDC, +5 VDC, -5 VDC (optional), +12 VDC, and -12 VDC lines across multiple pins.
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.
don't forget to reset the cmos when you reconnect the power, there is a clear cmos jumper on almost all desktops, it will be a jumper on 2 pins with one open pin, just move jumper to open pin +middle pin then back.
if comp still doesn't come on, could be cpu or mb