PSU Problem? Maybe?

[[DRuG]KillFrenzy]

While someone else was playing on a PC at home, the computer just suddenly turned off and he couldn't turn back on. He asked me to check it out.

The house power was fine.
The ON button indeed doesn't work.
Then I smelt something burning, which came from the PC.

Sniffing carefully, the smell was strongest coming from some ventilation holes in the PSU. Now, to support this, the 550W PSU appears to be dust filled, quite hot even after a few minutes, and was a really cheap crappy one that came with the case. Yet the PC was only on for half an hour or so during this day.

But the only thing holding me back about blaming the PSU is the computer is still partially powered. The computer is off, and the motherboard LED indicator is still lit.

Also, I turned off the PSU and wait for the power to drain from the motherboard, and after a while, I turned it back on. Right? Now I hit the ON button. The computer doesn't turn on, but I notice the fans move slightly, as if there was a trickle of power that actually came through. The fans only move once after each time I reset the PSU.

All other components of the computer seem fine. The only things that are powered while the computer is off is the motherboard, the USB keyboard, and USB mouse. Yet it cannot power up the computer.

I don't have a proper voltmeter to test out the PSU. I don't want to waste my money on a new PSU for nothing, if it was another part of the computer. You guys still think it's the PSU that's at fault?

[[DRuG]NikT]

I'd say PSU. But it is a gamble.. building PCs = savings but no warranty.

I trust you've reseated and dusted all components, and reseated while inspecting all connections and cables?

I often apply a process of reducing the system to it's minimum components, then applying a process of substitution and elimination of the rest.

Good luck - and always ground yourself first by touching the psu chassis before handling any complex component - especially ram/cpu/hdd, and dont get the white paste from the cpu on your fingers if u can help it - wash if you do get it on you.. makes you sick.

[[DRuG]KillFrenzy]

Substitution... I remember that, just didn't have enough time for it atm.

Time lengthly method though. I'll have to wait this out for a while when I've got time, and I'll report back if I find anything. I wouldn't recommend that I open up the PSU itself, myself, and dust it though. The other parts are pretty simple enough to dust. Yes I have inspected the power cables and made sure everything was plugged in properly.

And oh yeah, I've worked with building and upgrading parts myself before, and I've worked with that white paste before

Btw, you still get warranty for most individual parts that you bought for the PC, but not the PC as a whole.

EDIT: Oh yeah, everything above, like checking the cabling and dusting, is all internal, not external, meaning inside the PC box itself. This also applies to the sniffing part lol. The smell came from the internal ventilation of the PSU, that's where I sniffed, not the outside of it. So the PC box was open the whole time.

[[DRuG]NikT]

yeh you can still get quite a shock from the parts inside the sealed cpu box - even while unplugged... thus it's sealed.

I don't write this all just for you though, really, it's also for others that read on & see this classic case with all the classic approach suggestions, I guess.

[[SiK]DemonSeed]

When I couldn't figure out which part was the problem, I just ordered parts I thought was wrong from a Website that has a great return policy and thats how I widdled it down. And in your case it sounds like the PSU is at fault. 2nd cause could be the memory.

[DragonMaster]

Have you been experiencing any freezes before that happened? If so, I recommend you go inside the computer and give it a vacuum to get rid off the dust.

[[DRuG]KillFrenzy]

Well, I have ruled out this:
- It is not the problem of the memory
- It is not the problem of the graphic card
- It is not the problem of the drives

The CPU remains unchecked though, but the motherboard should output a CPU error if the CPU is at fault. I'm really suspecting the PSU now. What brand do you recommend though? It must be 450W or higher.

[[DRuG]NikT]

Meh... I've always replaced em with cheapies, I figure they all gotta die sometime.

Key thing to watch out for is that it has the right type of power switch to suit your system, some have press button on/off, others have a rocker switch on the back of the psu, while others again have both. I usually take the dead PSU with me to match it up, in a few cases the tech I took it to had a purpose built tester that he fitted to the old one to confirm it was definitely dead.

[[DRuG]KillFrenzy]

Okays... I'm pretty sure it was the power supply, I've just replaced the power supply with another 500W one, and the computer is up and running perfectly fine again

Costed like $50 for a decent one. Thanks for your help guys nevertheless. It helped me make sure the PSU was the problem