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View Full Version : Testing for failed PSU


MNBassman
08-29-2008, 08:46 PM
My friend's PC won't boot. No activity whatsoever when power button is pushed. I'm kind of a closet tech with no formal training so I was hoping someone could answer a question for me.

My first thought was a bad PSU. I don't have a known good device to replace it with so I shorted the green wire and a ground on the main connector to get the PSU to power up. I then checked the voltages on all three rails and they all checked out. Is this a good way to KNOW that the PSU is NOT the problem? What is the best way to know it is NOT the PSU?

Also I tried shorting the soft power jumper with no success. All connections seem to be sound so my thought is a bad CPU or mobo. All I know is that it's a pain trying to diagnose a machine with no activity at all; no beeps, fans, or sounds at all.

Am I on the right track so far or am I missing something? Any replies are happily welcomed.

mjc
08-29-2008, 09:20 PM
Bad RAM or motherboard can also cause a no boot....

Pull the RAM and any add in cards.

If it shows signs of life, start adding in things one at a time (power down, strap in...wrist strap or ground yourself between each check).

Also make sure that things like the CPU heatsink fan are working.