PSU possibly not working - what can I do? (HP Pavilion Slimline)

[R3troSim]

Ok, so I'm a newbie here on Tom's Hardware forums and a newbie with PCs.. However, I have a quick question which is mainly just for reassurance's sake.

So I'm servicing a HP Pavilion Slimline (actually for a separate issue to do with the HDD), and now I find I can't power it on.

All power cables are plugged in, and I get the green light on the side of the PSU to show it's getting power, but none of the other components are being powered.

So - this leads me to believe one of possibly two things.

1) The spongy power button; the PC did turn on sometimes, and didn't at other times. Maybe the metal simply wasn't connecting because the button didn't press down enough half the time.

2) The PSU needs checking/cleaning - basically something's wrong internally.

Number 1 is possible, but having stripped the rig apart - I'm now pretty sure the metal was coming into contact, and hence the power button is not at fault.

Number 2 (the PSU) is now what I want to check. HOWEVER - because I'm a lil anxious after having read about capacitors discharging instantly even after the unit's been powered off - I'm a bit nervous about opening the PSU and checking its contents.

So - I kinda have two questions..

First - what could be causing the no power problem? Is there something I missed, not necessarily a PSU problem (keep in mind: no isolator button on machine, all power cables checked)?

And second - if it is a PSU problem - a) is it safe to open the PSU after it's been disconnected for 24 hours, and b) what can I look for once inside to PSU to see if it's not functioning properly?

Ok - so that's more like three questions.. but I'm sure there's someone who will be able to point out something useful!

Thanks in advance!!


EDIT:
Ok - so I've decided I'm probably not going to open the PSU (too messy to do at the end of the day, esp. for someone as inexperienced as me). Instead I'm just gonna blast some compressed air through it once I get the canister. Hopefully that'll solve the problem!

If not, I'll edit the op again and leave it open for suggestions on why there's no power and what can be done about it!

EDIT #2:
I've cleaned out the PSU with a compressed air canister (there wasn't that much dust in it in the first place), and tried powering on again - nothing still.

Thanks mouse24 for the reply, I'll see what I can do.


EDIT #3:
ACTUAL SOLUTION FOR THIS CASE!!

As interesting as it would be to play about with this machine and try to diagnose the fault, I simply don't have the confidence or time to see this through. To confirm I have had to buy a new PSU (it's for a client PC after all) for the sake of time.

..With all that said, I'm pretty sure the PSU was also dead. No internal fan or other parts getting powered -- something just wasn't right with the power supply.

So this post is now solved (solution: bought a new PSU for the computer!)

PSU (160W) for HP Pavilion Slime s3542.uk (s3000 series) is manufactured by Delta Electronics, Inc.

Model no. is DPS-160QB-1 A

(Revision number for my PSU was 01F).

Just in case this helps anyone!


..And can't work out how to mark a thread as solved without selecting a post by another user (kinda solved my own problem xD ), so marked mouse24 as best answer.

 

[mouse24]

Does the fan on the PSU come on and start spinning?

If so, disconnect everything from the PSU and just connect a fan via molex then test that that is receiving power. (shorting the green a black wire on the 24pin)

If that successfully spins up plug everything back in and try the system again. If not then disconnect everything and try just the mobo/cpu + ram connected. Don't plug in anything else, no dvd/hdd/gpu/etc.

 

[R3troSim]

Does the fan on the PSU come on and start spinning?

If so, disconnect everything from the PSU and just connect a fan via molex then test that that is receiving power. (shorting the green a black wire on the 24pin)

If that successfully spins up plug everything back in and try the system again. If not then disconnect everything and try just the mobo/cpu + ram connected. Don't plug in anything else, no dvd/hdd/gpu/etc.

The PSU internal fan does *not* power on and start spinning.

The only indication of power running through it is the green light showing on the side of the PSU.

Since this PC's actually under service, and I think that the PSU has had it, I'm going to purchase a new PSU.

Thanks though for the help

EDIT: As interesting as it would be to play about with this machine and try to diagnose the fault, I simply don't have the confidence or time to see this through. To confirm I have had to buy a new PSU (it's for a client PC after all) for the sake of time.

..With all that said, I'm pretty sure the PSU was also dead. No internal fan or other parts getting powered -- something just wasn't right with the power supply.

So this post is now solved (solution: bought a new PSU for the computer!)

 

[R3troSim]

ACTUAL SOLUTION FOR THIS CASE!!

As interesting as it would be to play about with this machine and try to diagnose the fault, I simply don't have the confidence or time to see this through. To confirm I have had to buy a new PSU (it's for a client PC after all) for the sake of time.

..With all that said, I'm pretty sure the PSU was also dead. No internal fan or other parts getting powered -- something just wasn't right with the power supply.

So this post is now solved (solution: bought a new PSU for the computer!)

PSU (160W) for HP Pavilion Slime s3542.uk (s3000 series) is manufactured by Delta Electronics, Inc.

Model no. is DPS-160QB-1 A

(Revision number for my PSU was 01F).

Just in case this helps anyone!


EDIT: Can't work out how to mark a thread as solved without selecting a post by another user (kinda solved my own problem xD ), so marked mouse24 as best answer.