Desktop wont power up

Opie · 12-06-2005, 02:06

Loaned it to my brother. Mistake #1

He said that his dog unplugged it, and when he plugged it back in he heard a "sizzle."

Now it does nothing, won't power up at all. The fans don't even come on.

Where should I start? Should I buy a new power supply and go from there?

Toyman · 12-06-2005, 05:13

Check the back of the computer where the power plugs in, on some models there is a switch there for the power supply. Make sure that's on.

If that doesn't work, it's probably a bad power supply.

NRA_guy · 12-06-2005, 05:32

Check the power cord and the plug on both ends with an ohmmeter.

You probably know this, but make sure it's plugged in firmly into the back of the PC.

Also, make sure the circuit has power (no tripped breaker or something.)

If you are getting power inside the PC (check carefully with a volt meter) it's probably the power supply. I have replaced mine 3 or 4 times. They last about 9 to 18 months. But I have seen power supplies on 3 month old Gateways and Dells go out.

HVAC-TEK · 12-06-2005, 06:39

Your problem could be one of two different things. The power supply or a component grounding out.

If you’re up to tinkering with it, you can test for a “ground out” by popping the cover and removing all the cards, and remove all but one memory stick from the mother board. Sometimes you find that in this stripped down condition the computer will work. Determine the trouble part by powering the unit down each time and replacing the cards one at a time. The bad card will prevent the computer from working.

Now, if that doesn’t work, we need to decide if it’s the motherboard/processor or the power supply. If you have an ATX power supply, you will have a large white power jack going to the mother board

IF YOU HAVE TWO JACKS, THAT ARE THE SAME SIZE, THAT PLUG INTO THE MOTHERBOARD IN A SIDE BY SIDE CONFIGURATION, YOU HAVE A 'AT' STYLE POWER SUPPLY. DO NOT PERFORM THIS TEST you MAY DAMMAGE YOUR SUPPLY.

Ok, now that’s over with heres the drill. You leave all the other parts plugged into the power supply. You UNPLUG the single white power jack from the motherboard. Locate the green wire on the jack. With a small wire, jumper the green wire to any ONE of the many black wires found on the jack. (All the blacks are basically grounds) (The green is only 12 volts, so don’t worry) This will power up the power supply. If it’s good, you should hear the power supply fans kick on. If it’s burnt out, nothing will happen. If it fires up, do not leave it jumpered for more than a few seconds, as this could be damaging to the supply due to lack of "load'.

If your supply fires up usually its ok. If you have a multimeter, you should find that you get either 12, or 5, or 3.3 volts depending on the color wire. (One lead on a color, the other to black)

If it’s a bad supply, replace it from another found online (better prices). If you have a dell you’re screwed, because dell power supplies are often wired differently than standard power supplies (although they use the same jacks). Putting a non-dell supply on a Dell computer often fries the motherboard.

KIM

Washington,D.C. · 12-06-2005, 19:33

Take the 120 volt-220 volt switch on the back and switch it back forth.Sometimes this resets a protection circuit breaker.

Opie · 12-07-2005, 00:55

Thanks Guys!

The power supply was shot.

My brother in law had one laying around that fit, he switched em out and it works fine so far.

Thanks! Brian

HVAC-TEK · 12-08-2005, 14:29

Quote:

Originally posted by Opie
Thanks Guys!

The power supply was shot.

My brother in law had one laying around that fit, he switched em out and it works fine so far.

Thanks! Brian

Just make sure that your replacing it with a similar size.

If the old one was 400w, you may not want to downgrade to a 250w power supply. Larger is better, but going smaller can sometimes make the system quirky or unstable.

Nice to see you got it working.

KIM

Scavenge the fans from the old supply, they may come in handy in future.