[Cybercat]

The computer I use for games and movies has decided to have issues. I *think* there's something worong with the PSU, but before I spend money buying a new one I am explaining the problem here hoping somebody can confirm this or suggest what else it could be.

When I switch on the computer it starts normally, but after a while, usually about the time I get the bit where you log in but sometimes a bit after that, it will switch itself off. Sometimes the picture on the monitor wil dim a bit before it happens, but not always. A few seconds after the computer has switched itself off, it will switch itself back on for about a second, the DVD player will spin up, but it will switch off again before it even gets to display the bios splash screen, wait a second or two, switch on again, and of, and it will repeat that until you pull the plug.

I know it's not a software issue becuase it happens no matter which of the 3 OSes installed I try to boot into, and when it goes to it's on/off thing it doesn't even get as far as the bios. As I said, I *think* it's a problem with the PSU but before I buy a new one I'd like other people's thoughts.

The annoying thing is that that computer normally is on almost 24/7, I hardly ever switch it off. This time it wasn't downloading anything so I figured I'd save some money on my power bill and when I switch it back on this is what I get

[linuxelf]

That sounds like one of two things to me. Either the PSU is failing, or the CPU is overheating. If the CPU fan is working, I'd start with the PSU. Do you have a multimeter so you can test what voltage it's supplying?

[Waycos]

A lot of times when the PSU goes (or starts to), you can hear an audible whine coming from it.

[Cybercat]

Unfortunately I have no multimeter. I'll check whether the CPU fan is working or not and if it is, I'll just assume it's the PSU and replace it.

Update: When I saw that all fans were working properly, I bought a new PSU and replaces it. The computer works again, so I guess that was indeed the problem (unless it was a loose wire somewhere that got plugged in properly when I connected the new PSU.)

This post has been edited by Cybercat: 02 September 2009 - 11:30 AM

[SaintArthur]

In my experience (every day 5 - 10 machines come in) it's nearly always because of dust. We have had a compressor in the shop for the last three years and it was the best purchase ever. An idea is to bring it to a garage and blow it out with air from the hose. I know you've fixed the problem with the new PSU but still I would recommend doing it.

[Cybercat]

I don't have a compressor, but I did try vacuuming it before I replaced the PSU as I suspected a dust problem too. Unfortunately, that didn't do the trick.

[Joe Dalton]

I like how far we've come but dust can still make us tremble

[Scrubber]

I like how far we've come but dust can still make us tremble

Vacuuming is actually not a very good idea. You can cause a LOT of static electricity and short out components. Using a can of compressed air to blow out your machine(take it outside, you'll thank me) once every 6 months or so is a good practice.

And once the PSU starts to go, there's very rarely any chance of bringing it back(at least in my experience)

Good to see you got it going again!

[Antonius]

Vacuuming is actually not a very good idea. You can cause a LOT of static electricity and short out components. Using a can of compressed air to blow out your machine(take it outside, you'll thank me) once every 6 months or so is a good practice.

And once the PSU starts to go, there's very rarely any chance of bringing it back(at least in my experience)

Good to see you got it going again!

QFT. I've seen that happen to machines that were vacuumed, reassembled & switched back on.
1 dud computer & 1 dud circuit breaker later, the boss learned a valuable lesson: Let the guy you pay to do Tech Support & Maintenance do his job, it's cheaper that way.

You can bring a PSU back if you've got solid soldering skills, spare capacitors (which are usually what go), and time.
I had a friend try this, but he mixed up the rating for the capacitors. And proceeded to EMP his apartment. Quite cool...