Puter Power Problem
June 12, 2005 5:42 AM   Subscribe

Why does my computer not like its lead?

I'm running a bog-standard Packard Bell i-media (about 5 years old), 1.4GhZ, 40MB, Windows XP machine. Completely standard machine, state-of-the-art when I bought it, positively stone-age now, but does what I need it to do. I'm using only 27% of the available HD space, so there's still plenty of life left in the old thing.

But for about the last month or so it's been playing up in a peculiar way and I've found nothing on Google to explain why.

I'm in the UK, so the power to the computer is supplied by a standard power lead on a UK 3-pin fused plug, plugged into the mains via a surge protector.

Over the last few weeks, after the PC has been switched off, it won't power up again until I've unplugged the mains lead from both the PC and the mainsl and replaced it with a different lead. If I unplug the same lead and put it back, it doesn't work, it's almost as if the PC knows (yeah, yeah, I know, it's only a machine) that I'm trying to put the same lead back in. But I put a different lead in and - hey presto! it works!

Even if, once I power down, I take out the lead and then the next day put it back in again when I power up, the PC won't start. I have to swap it for another lead (I have three that I am alternating).

In all other ways, the PC is running well. I thought it might be due to overheating, but it's running at between 39C and 42C, so I don't think it's that. As far as I am aware, there's been no power surge, it's not cut out or shut down for no reason while I've been using it.

Any ideas guys?
posted by essexjan to Computers & Internet (12 answers total)
I'm not there to evaluate the veracity of your power cord woes, but I'd say it's highly likely that your power supply is going out. If it's not that, it might be a motherboard going bad. On a more home-built PC you could just replace either of these, on the packard bell, I don't really know. The power supply maybe, the motherboard I kind of doubt it.

Not that you asked but since I'm here, you could probably make a "new" PC by taking most of the old components and just getting a new mother board, case, ram and CPU. Bargain basement versions of these can total up to less than USD $200
posted by RustyBrooks at 7:23 AM on June 12, 2005

The only mechanism I can think of for the behavior you describe that's even vaguely plausible is that a socket somewhere (either inside the lead where it plugs into the PC, or in the surge protector where the lead plugs in) has got old and tired and lost its firm grip on its corresponding pin.

Try switching just the computer end of the leads that go to your computer and your video monitor, and see whether the necessity to rotate leads stays with your computer or moves to your monitor.

If it stays with the computer, get a bright light and check the pins in the back of the computer where the power cable goes in for signs of tarnish; if you find any, clean it up with fine sandpaper. Wear rubber gloves for this, and don't use steel wool - computer power supplies can retain enough charge to give you a nasty little kick if you stick your bare finger in their pins.

If it moves to the video monitor, the fault is most likely at the surge protector end (some of those things have really iffy socket contacts). If you have multiple outlets on the surge protector, use a different one and see if the problem goes away. If not, try plugging directly into the wall outlet: if that fixes things, replace the surge protector.
posted by flabdablet at 7:55 AM on June 12, 2005

If not, try plugging directly into the wall outlet: if that fixes things, replace the surge protector.

I've tried that, but it makes no difference.
posted by essexjan at 8:33 AM on June 12, 2005

Change the PSU.
posted by kenchie at 10:45 AM on June 12, 2005

Yep, ditch the power supply, and buy a good one.
posted by Manjusri at 11:14 AM on June 12, 2005

Third the 'ditch the power supply' ... although it could be the motherboard's power-on circuitry, which has been known to go bad. I've got a bad power circuit on my mobo, and I need to unplug the power lead or shut off the switch on the PSU until the little green light on the motherboard goes out before I can power-on the computer.
posted by SpecialK at 12:21 PM on June 12, 2005

Put up a large plush toy prize for whoever can figure it out, charge people $1 to marvel at the mystery, and take the show on the road.

I too am stumped, but like the people above, guess that it's likely in the connectors or the PSU. Since the connectors are in the PSU, then changing the PSU seems like a good bet.

If you can borrow a PSU, you probably don't need to physically install it to hook it up for a test run - just switch over the internal cables. You could probably have your computer running on it in a few minutes, then test to see if the problem goes away. If it goes away, then buy and install a new PSU.
posted by -harlequin- at 1:13 PM on June 12, 2005

The most technical thing I've ever done with this PC is to replace the CD-RW drive, and even then I was hyperventillating when I removed the case.

Is replacing a PSU more complicated than that? Can anyone point me to a 'how-to' web page for dummies?

BTW, thanks everyone.
posted by essexjan at 2:24 PM on June 12, 2005

its pretty easy. If you replaced the CD-RW drive then you have already unplugged one of the internal power cables and plugged it in again.
you just have tounplug all the power cables from your motherboard and all the compones(cd-rw drive, floppy, harddrive, ect). And then plug in the cables from the new PSU.
There should be enough slack to try it out with the new PSU outside the case, but its not that hard to remove the old one, its probably just a matter of finding all the screws that are holding it on.
Also all the power cables have special connectors on them, so you dont have to worry about pluging the wrong cable into the wrong hole.
posted by Iax at 4:06 PM on June 12, 2005

Did you try swapping the equipment ends of the leads that power your computer and your monitor? Just interested in the result.
posted by flabdablet at 4:35 AM on June 13, 2005

Did you try swapping the equipment ends of the leads that power your computer and your monitor? Just interested in the result.

Not 100% sure what you mean by this but I did unplug the power lead from the monitor and try it in the puter. It didn't work until I unplugged it from the computer and the mains, put it in again and powered up. Then it worked.

So it's not a problem with the power leads, I've tried four different ones now that all work fine. It's something in the CPU.

I'll bite the bullet and replace the PSU.
posted by essexjan at 8:37 AM on June 13, 2005

Yes, its very easy. Count the number of pins on the connector that goes to the motherboard, and make sure you get the same connector on the new one. Buy one (at least 400w) from newegg.com. Read the reviews to get a feel for the quality.
posted by Manjusri at 1:19 PM on June 16, 2005

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