desktop erratic starting

  keef66 10:31 19 Dec 2008

we have a 6 yr old pc which, despite the march of technology, has proved perfectly adequate for our family needs, and is still in almost constant use by our younger son doing A levels.
Recently it's started being a bit reluctant to start up, having to press the power button repeatedly until it eventually fires up.

Initially I suspected the switch on the front panel, so I swapped the power and reset switches and their connections to the mobo. No change. (and buggered up the DVD-ROM drive when taking the front panel off!)

Then I noticed that if I switched on the power at the socket then waited 30 secs before hitting the case switch it would work first time. With the side off the case I could hear a very faint high pitched squeaking noise when the power socket was switched on.

I'm now suspicious that something in the psu is on the way out; maybe a capacitor is taking longer to charge than it should? Or could it be a motherboard component? Does any power get to the mobo before the case switch is operated?

At the weekend I'm going to put in an old but working psu and see if it solves the problem. Any other suggestions??

  birdface 10:36 19 Dec 2008

Old computer make sure the air vents are clear of dust and fluff if so inside will need cleaning out as well.When inside make sure all of the fans are working Ok.

  keef66 10:50 19 Dec 2008

It gets mucked out regularly and all fans are OK. Once it's up and running it's perfectly stable; Speedfan reports normal temps, so it's not a cooling / ventilation issue.

Just wanted to know if it could be a mobo problem or if the psu is the likely culprit.

It's already cost me £17 to buy a replacement DVD drive (but it is an upgrade to a modern rewriter) but if the mobo is on the way out I'd have to question the wisdom of spending any more money on it. It's a socket A Athlon XP, so I'd probably need to buy a mobo / cpu / ram bundle, and probably wouldn't be able to reactivate the Windows XP OEM, and all my drives are IDE connectors......

In that case I'd just buy a desktop replacement lapptop and a usb caddy for the old HDD to transfer all the stuff.

  birdface 12:52 19 Dec 2008

PSU is probably the problem then.There is a way of testing them.I used to keep it in my favorites but lost it due to reformat.Maybe someone else will be able to give you a link to it.I am no expert so maybe better waiting for someone else to give you the advice that you need.

  Ozy 13:07 19 Dec 2008

power does get to the mobo when you switch the power on at the wall,i have an old computer
that has an asus mobo when i switch on at the wall a green light comes on on the mobo then i have to press case button to start,
though i cannot see that this info helps you
Maplins sell a psu tester for about £11,
but you could buy a psu for that from a computer market,

  keef66 13:49 19 Dec 2008

I was thinking that if absolutely no power went to the mobo before the case switch was pressed, the squeaking noise would have to be the psu.

I still have the cheap but functioning psu which the pc was supplied with. I upgraded it to an Antec which is the one currently under suspicion.
I'll put the original back in and see what happens.

  Wak 14:19 19 Dec 2008

I have a similar problem to you. My PC is nearly 7 years old and sometimes has trouble starting with the bottom Start button.
Sometimes the fans and the red/green lights operate for a few seconds and then stop. This means switching off and then on again at the wall socket until things are OK.
Other times the red/green lights and the fans stay on but nothing boots up. This then means pressing the top restart button.
I've also noticed that when going into the BIOS, (by pressing DELETE on booting up), the lines of text (operation descriptions) are missing but the selected or required actions are shown.
Surely this must mean a faulty file in the BIOS??I put all this down to a corrupted BIOS file as it all occurs before any of the system is loaded and I am at present looking into sourcing and replacing the BIOS file.
At first I also thought it was a faulty bottom switch but it proved not to be so.
Once up and running, the PC is just as great as it has been for the last 6 or so years.
Any other ideas or suggestions would be very welcome from anyone???

  skidzy 14:39 19 Dec 2008

hi keef66 been a while :-))

yes the mobo does have power before the case switch is depressed,as you can short the mobo without actually pressing the case switch and this in turn will fire up the computer.

It certainly does sound like the psu is deteriorating and does not like a cold start.

As this is an old system,maybe a cheap psu is worth a try if you do not have a spare to hand.

The socket 478's i build all have a budget psu installed from Ebuyer.I would not normally recommend a budget psu,but in this instance,i think it would serve you just fine.

Some of the ones ive used over the last year
click here
click here
click here

I am assuming its an ATX case.

  keef66 12:53 19 Jan 2009

Hi Skidzy; yes it has been a while. I've been off becoming obsessive about road cycling for a few months. More expensive hobby than tinkering with pcs!

Finally prized the teenager off the comp for long enough to take it apart. Put in the original very tinny psu (and the shiny new dvd writer) and all is now well. It starts up first time so the culprit was obviously the reassuringly heavy Antec psu.

Glad it wasn't the mobo; I've only got to keep the thing going for another 18 months then the youngest will be off to uni and we can buy ourselves a big laptop to replace it.

I'll tick as resolved now

  skidzy 18:29 19 Jan 2009

Glad your sorted ok Keefe....lets hope it holds out for now :-))

  keef66 11:49 03 Mar 2009

AAAArgh! It's started doing it again. Power on at the wall, sometimes pressing the case power button starts it straight away, sometimes we have to leave it a couple of minutes before it will cooperate. Either it wasn't anything to do with the psu, or something's going wrong on the mobo and damaging the psu's. If it has a mobo fault then I think the laptop purchase will be brought forward. Not worth spending on a mobo / cpu / ram bundle since we only need it to last another year or so.

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