How do I determine if a power supply has gone bad?

[Inchworm]

I leave my computer on 24/7. I came home last night from 10 hours of kid-watching, and my computer was off. The switch was non-responsive.

I need computer for several reasons and ain't no Rockerfeller so I must figure this one out.

I'm getting power from the outlet to end of cord. Also, ahen I plug it in a green light lights on motherboard. I removed all covers and saw no obvious breaks in wires around switch. There were no odd smells like burning plastic, etc.

Hmm..
The monitor knows when it is connected if that means anything. When I removed monitor connection the screen said No Signal.

I'm fairly comfortable with a multimeter if there is anything that makes sense testing. I am considering testing the main connection from power supply to the mother board.

Any ideas I may be missing? It's like I have a friend in the hospital and I'm the only doctor. :cry:

:shrug:

:hi:

[CK_John]

1. You can test a PS with a paper clip across the green and black pins near the center of the

20 pin connector. You can use rubber gloves if worried about shock.

[Duer 157099]

2. If the fan on the power supply does not come on...

then I would guess it's a dead PS.

Not unusual to have to replace a PS, especially if you leave it on 24/7.

You can get one from NewEgg for $30 or so.

[Inchworm]

3. Welp, evidently PS isn't the problem

I took the PS to a friends and it worked like a charm on his comp...

He said maybe loose switch or bad switch. As much as I hate to I think I'm going to cut the 2 wires going to switch and see if it works. Well, after I makes sure all the connections are sound.. and.. after I sober up. My friend and I had a few beers. :beer:

:banghead:

[EvolveOrConvolve]

4. I have two guesses

1) A bad motherboard - even thought it's getting power, it may have one or more fried bus lines on it. Perhaps there was a power surge that caused it while you were away? Those happen in the summer time a lot with air conditioners going off and on all the time.
2) A short in the power-on switch. Check the wires going to the power button carefully to see if there's anyplace where they are frayed or even slightly cut. You may be able to patch it up if that's the case.

[Duer 157099]

5. For future reference, there's an inexpensive card you can get...

for a few bucks on ebay, a POST tester. I have found it very useful for situations such as yours.

Here's a description from one such item on ebay:

Motherboard Diagnostic Card, also known as a "POST Card" (Power On Self Test), is used to test & diagnose motherboard problems.

If your computer has problems powering up, freezes for long periods of time, suddenly shuts down unexpectedly or shows other signs of hardware problems - this card can diagnose your problem. It can even pinpoint problems you don't even know you have!

Specification

*
Both ISA bus and PCI bus are suitable
*
Court defects by difference sounds coding with build-in speaker.
*
It can diagnosis the motherboard signal which show the problem of CPU, Memory, display card and so on.
*
Wrong plug or direction will be not affect the operation of PCI or ISA slot.
*
LED displays shows diagnosis result of motherboard. Especially helpful to pinpoint where is the problem when power on the computer and find no display or machine hangs up. PCI bus reset and CLK signal working indicator. When each LED indicator is on it indicates its respective signal is fine.
*
Support the power source working indicator -- +5V,+12V,+3.3V and 12V(When indicator LED is on to indicate its respective power is fine, otherwise to indicate its respective power is failure.)
*
Fully compatible with any kind motherboards which has the PCI and ISA bus slot.