P.C Power supply probs....any idea's?

Question

If a pc doesn't power up, what are the steps taken to find the fault.

If I remove the power unit from the tower, should it fire up if I plug it in independantly?

I've tried two other PSU's and I can't believe neither of them work...Is the board suspect then?

Answer 1

try pluging in one device at a time, ie attach the power to the motherboard then plug in a harddrive, then add a disk drive etc..

if it still dont work, then plug in the hard drive direct, if it works then the mobo could be knackered.

Answer 2

When you press the power button on the front of your machine do the lights on the front come on? If nothing else happens, your almost certainly right, and you'll have to replace the psu.

However, and full description of the problem would help.

A PSU is powered through a circuit on the motherboard from the switch on the case front these days, it wasn't always so. So to take the psu out, plug it in and get it to turn over, well you need to be able to earth it, which isn't happening, because that is done by the board connector. It can be done, though it is RISKY.

Probably it would be easier to take the psu out of the machine it is in and connect it to a working one.

Answer 3

A PSU needs to have a constant load on it at all times, a hard drive will not cut it.

If you search on the net you can find how to start a PSU by itself.

You can try that for 1 second, if it powers on you know it's good, and shut it off immediately.

If it doesn't then get a new PSU.

Answer 4

The best way to test a power supply is with a power supply tester.

They aren't very expensive. I got mine from Tiger Direct. Item number ULT31553. Cost is about $20.

You can test the power supply outside the PC with this. Can safely check all of the different circuits.

Mine has never let me down. If it says it's bad, it's bad. If it says it's good, it's good. Takes the guesswork out of it.

Answer 5

No, you need to short the connectors before it will work, but unless you know what you are doing, a BANG is a great possibility.

You should get a PSU tester, or a cheap power supply if you are not getting any power at all.

Answer 6

first thing is to check .. the connector on the motherboard.. see if its melted or scortched. that happened to me..

the cause, adding a new pci card, that drew too much power.

the solution was to upgrade to a higher wattage psu.

if its shutting down, it might be trying to stop damage.

or maybe you have a short, even things like the how the casing / mobo is mounted might be causing the issue.

if u have added a new card / hard drive , i'm guessing too much drain.

testing with another psu is always elpful though, but remove some of the wiring to stop any strain.

Answer 7

Please do not mess with power supplies, firing it up independently sounds very dangerous to me, and people saying shorting pins out to do so is not the way to fault finding, at least get it checked by a PAT tester professional, if need be try another good PSU that you know is good.

Answer 8

How old is your PC?

If less than a year, contact the company for the warranty work.

If over a year, Maplin were doing a 450W PSU for £20 (£10 off the RRP).

Answer 9

No--a power supply needs a load to fire up. Plug a hard drive into it.

Answer 10

There can be two problems either ur SMPS is gone or ur motherboard is having problem. Try connecting a new SMPS and if ur system still doesn't fire up then get ur motherboard checked.