PSU Problem?

[Sar]

Quicky:

My PC knocked itself off while I was AFK (on the lappy atm), and when I came back it wouldn't turn itself on at all.

There are several indicator lights on my mobo (ABIT-TH7 II running a P4 1.9) stating:

Reset
HDD
5VU (I think)
Power


The only one lighting up is the one next to 5VU, nothing else is coming on and there's no activity otherwise.

Any ideas?

I was thinking it was maybe a blown PSU, but power is reaching the mobo in some fashion...

TIA

 

[wyrd_fish]

i had a similar prob...

i thought it was the PSU, nut it turned out the southbridge chip was fried... had to get a new mobo, bah...

see if any of the chips on the board a VERY hot, my southbridge burnt my finger, while or just after running the PC.

also try the mobo and the PSU in other comps...

 

[xane]

If its a thermal cut out you have to physically disconnect the PSU plug from the mobo to reset it. Try that first.

 

[Sar]

Nope Xane, no dice.

The light on the mobo that IS lighting up has 5VSB beside it.

This is the light I mean:

Loath to buy a new mobo, cos I'm skint atm...

:/

 

[kameleon]

So no HDDs pwering up?Have you not got a spare PSU to test ?

try unplugging all hdds and cds and turn it on again

if it boots eliminate the dodgy ide device.
If not ,new PSU

 

[Tom]

I'd be surprised if the psu has in any way damaged the motherboard by failing. This would indicate poor design.

I would suggest borrowing a case/psu off somebody else. If you know a thing or two about electronics, check the output of the psu to see if the correct voltage is being supplied.

 

[xane]

You can try resetting the BIOS, might work

 

[Xavier]

ok, three questions, bear with me

1. is your keyboard USB or PS/2?
2. with the power plugged in (and any switches on the rear of the PSU switched 'on') do any of the keyboard lights work?
3. Have you tried unplugging the PSU from the wall and motherboard, hooking it back in and firing it up?

I'd try unplugging the ATX connector and the mains feed to the PSU for starters, give it 10 minutes or so, and before sticking the mains lead back in hit the power button (once you've reconnected the ATX).

If that doesn't work you can try the below but note I am NOT RESPONSIBLE for any electrocution or damage to your kit.
The procedure I'm outlining is perfectly safe if you understand what you're doing, so if you have any doubts say so and I'll take you a couple of instructional photos to help you along.

Plug a CD-ROM into one of the molex connectors of the PSU (unplug it from all other components in your system, including the motherboard) and short wires 3&4 on the ATX plug with a length of coated mains wire (they're adjacent to one another, one is green, the other black, on the side of the plug with the clip). Wire order is 1. Orange 2. Blue 3. Black and 4. Green in that order from the corner. If you then plug in the mains and hit your power switch the PSU will be turned on by the connection you've made, simulating the ATX power button and the CD-ROM should kick in.

Watch to see if the drive light comes on, if it spins up, and if you can eject/close it as you would usually.

If it doesn't congratulations your PSU hath failed.

If it does however you're going to need to remove your motherboard from your case, check for shorts on the underside from an undeeded riser or something and then run it out of your chassis on an electrostatically shielded surface to isolate the real fault.

I've seen systems fail like this for all manner of reasons, PSUs die, fuses die, those are the obvious ones. We've got one PC which we take to events quite regularly which stopped working after 9 months of problem free use (and no tinkering) - turns out a thumbscrew was trapped above the PSU and one day it just fell down between motherboard and chassis, somehow tripping the sytem power... These things can happen, fingers crossed yours is something equally as slight, rather than any hardware being really b0rked.