PC won't start "sometimes" - PSU problem?

[neilencio]

Just a heads up, this is not my main PC. It's an old one that still has enough ooomph to run current games so I don't want to replace too many parts to the point that I could have bought a new one. I just want to make the most out of this (replacing the power supply is okay, though, since that's what I suspect to be the culprit. I'm just not sure and I don't want to waste money on buying a part if it's not the problem, or if the rest of the components are about to break down anyway)

So the problem is that it sometimes won't power on. No fans. no LEDs.

Details:

• It usually happens after being shut down for long periods of time (I use it as a torrenter/downloader so it's 24/7 most of the time). It's not all the time, though. Most of the time it starts without any problems. The only consistent thing is that when it happens, it was after being shut down for long periods. I cannot reproduce the problem by simply turning everything off repeatedly (or even after an hour or so inbetween starts). There are also times when the PC would start flawlessly after being off for weeks. It's really random.
• The monitor is not connected to the PSU, I run it directly through the UPS. When the problem occurs, the monitor is okay but the CPU isn't (so it probably isn't the UPS causing the problem)
• I can get the PC to start again by either removing the power cord at the PSU or at the UPS, and reinserting them, or moving them to a different socket (if I do the UPS thingie). Either method works, so it's probably not a loose connection on the PSU.
• The PSU is only 400w not true rated, but it's not a gaming machine (e8400, GT 440 *no external power needed*, no optical drive, 1 sata, built in everything else) so I doubt it's a problem of not having enough juice.
• The problem was not there when it was new, but it's been there through several upgrades (mainly just the videocards and CPU, it went from having an 8400gs, to a 9500 GT, to gt240, to GT 220, and now a GT 440. The cpu has been upgraded once from a dual core e5200 to the current e8400. It was already there during the e5200 days)

So, any advices on what I should look at? I am not handy with electronics and I don't have a voltmeter so I probably won't be able to poke around at the random wires without electrocuting myself and gaining powers beyond the ken of mortal men. If it's the motherboard I'd probably just let it go on with this problem until it dies completely.

(additional Q in line with the above: If I don't do anything about the problem, will it get worse and kill other parts or will I just have to live with the hassle of getting it to start?)

EDIT: I just remembered, I can't try to swap the other PC's psu because it's in the other house (I try to keep a working pc at our house, where I stay most of the time, and at the in laws, the two places are very far from each other)

[Hobie-wan]

Likely a flaky PSU, yes. My old Pentium 100 got a bit odd with the shitty power we had in a house rented with friends. Sometimes I'd hit the power and there would be a light popping noise coming from the PS, but no booting. I'd have to pull the power cord out, wait 5 seconds, then hook up and try again and all was well.

However since you have another PC, you can try with the other one and just do without your main for a day. reboot or shut down periodically for a bit and see how it goes.

[neilencio]

Thanks Hobie. I was afraid it was the motherboard (as it's already old), I'll take the jump and get a replacement PSU. I remembered that one of my local sellers allows people to return items within 3 days (even if it's not defective). I will probably take advantage of that one.

How about my other question: If I don't do anything about the problem, will it get worse and kill other parts or will I just have to live with the hassle of getting it to start?

[Hobie-wan]

If the PS failing, then yes it could completely die and take other parts out with it if a capacitor or mosfet blows up since that would likely send a surge at the PC. Though if a capacitor is leaking and drying out it might just get worse until one day it just refuses to start anymore.

[neilencio]

Got myself a Silverstone true rated 500w PSU. It's been chugging along nicely and I notice no problems.

A few things, though:

- this new PSU is twice as heavy as the generic one. Must be all the magic electricity making stuff inside.
- My cpu temps consistently dropped by 3C (perhaps I was stressing the previous PSU? causing a lot of heat? )
- the shielded cables actually look spiffy, and are much easier to organize.

[Hobie-wan]

Got myself a Silverstone true rated 500w PSU. It's been chugging along nicely and I notice no problems.

A few things, though:

- this new PSU is twice as heavy as the generic one. Must be all the magic electricity making stuff inside.
- My cpu temps consistently dropped by 3C (perhaps I was stressing the previous PSU? causing a lot of heat? )
- the shielded cables actually look spiffy, and are much easier to organize.

Shitty PSUs can make 'dirty' power that has horrible waveforms or power that fluctuates which can stress the rest of the PC. Bad power regulation, or just heat from the PSU itself if it wasn't very efficient could have been making everything warmer in your case. Twice as heavy is good, it likely means there are more of the proper power filtering components in it and has better heat sinks to cool it off. This is why you shouldn't buy bargain basement PSUs. Everything else depends on them to run well.

Have a look at this article on crappy PSUs, especially page 4 to see what I'm talking about with horrible ripple. http://www.jonnyguru.com/modules.php?na ... ry&reid=71

Glad it made your PC better.