Power supply problem?

[Guest]

My second pc in another room must have just switched itself off. I tried to
switch it back on and it didn't power up at all. I unplugged it took the
cover off and looked for any loose connections, pushing the cables in firmly
as I went along.

I plugged the machine back in and powered it up fine first time. The lights
on the case came on. No problem.

I re-sited it where it usually goes and tried to power it up again. It came
on, but the lights on the case didn't come on. Then I switched it off and
looked inside again - nothing obvious, no smells or anything, all fans
free-moving. Plugged it back again and the machine was fine, windows booted,
I left the room whilst the scandisk ran (winme!) and I returned about 5 mins
later. It was off. Now it doesn't power on at all. I suspect if I try
leaving it unplugged again for several minutes and try again, this process
will probably be repeated.

So, any thoughts? Is it a faulty / dead power supply? Or can a bad
motherboard do this? I think its the power supply because the machine when
it doesn't power up really doesn't make any attempt to...

 

[kony]

My second pc in another room must have just switched itself off. I tried to
switch it back on and it didn't power up at all. I unplugged it took the
cover off and looked for any loose connections, pushing the cables in firmly
as I went along.

I plugged the machine back in and powered it up fine first time. The lights
on the case came on. No problem.

I re-sited it where it usually goes and tried to power it up again. It came
on, but the lights on the case didn't come on. Then I switched it off and
looked inside again - nothing obvious, no smells or anything, all fans
free-moving. Plugged it back again and the machine was fine, windows booted,
I left the room whilst the scandisk ran (winme!) and I returned about 5 mins
later. It was off. Now it doesn't power on at all. I suspect if I try
leaving it unplugged again for several minutes and try again, this process
will probably be repeated.

So, any thoughts? Is it a faulty / dead power supply?

That is likely.

Or can a bad >motherboard do this?

Less likely but still possible.

I think its the power supply because the machine when
it doesn't power up really doesn't make any attempt to...

Take voltage readings with it in the "should be on but
isn't" state. Disconnect the power supply from everything
but a load (like an old hard drive or optical drive) and
short the PS-On lead (Pin 14, green wire) to gound and again
take voltage readings. Re-examine the board, including
capacitors. If you have a 2nd, known viable power supply it
could be useful to try it, perhaps stripping system down to
bare essentials by disconnected any/all parts not essential
towards posting, leaving only video, 1 memory module, CPU,
and heatsink/fan.

http://69.36.189.159/usr_1034/atx_on.gif

 

[DaveW]

Sounds just like a failing Power supply unit to me.

 

[dannysdailys]

Sounds like the power supply. Just run to CompUSA and pick up a ne
one. If it doesn't fix it, take it back