Almost dead computer

[ARW]

Any ideas?

It turns on and the fan runs. There is nothing else - no bleeps - no screen. The led that shold flash when the hard drive is working is not lighting up.

I suspect a duff HD but ideas are welcome.

[Tim Watts]

On Saturday 02 November 2013 15:38 ARW wrote in uk.d-i-y:

Hi Adam,

I don't think so - lack of a beep indicates the system is not going through the POST/BOOT process.

I have a computer (server) that randomly does that (6 years old).

Try power cycling a few (10) times.

Then try removing the video card, unless it's on the mainboard. You won;t see anything with no video obviously, but it should beep.

The video BIOS hooks in as part of the POST/boot so sometimes a duff video card can do this.

[Malcolm]

Dead PSU? Something like foil in one of the USB ports

Had both of these at the school where I worked

Malcolm

[Dave Plowman (News)]

No startup sequence? That's done by the BIOS so doesn't need the HD. I'd check the power supply for 5 volts first.

[ARW]

Everthing is "on board" apart from a wireless card that I have remove to see if that is the problem.

BTW its an acer Aspire M1100 if that helps.

[GB]

There is a semi-standard procedure to go through. Remove all expansion cards and USB devices. Make sure that all the memory is firmly seated. Get rid of some of the dust. Try rebooting it.

I agree with Tim that the one thing it does not sound like is a duff hard disk. I would be very very tempted to remove the cables connecting the hard disk. Most people do not back up their data properly, and if the hard drive is still working the last thing you want is to fry it at this stage, however unlikely that is to happen.

Do you have any more PCs? I ask because the standard way of diagnosing faults is to swap parts until the machine works again. If you have a known good PSU, you could swap that in.

[Tim Watts]

On Saturday 02 November 2013 15:57 ARW wrote in uk.d-i-y:

Ah.

Oh yes, and check the PSU like someone else just said - should have 12V and

5V on one of the 4 pin Molex connectors after pressing the ON button.

However, those are switches off when the PSU is in standby mode.

The only power that is on all the time is the standby rail.

You could maybe stick a voltmeter on pins 9 and 24 of the motherboard power connector:

Should be +5V.

Tim

[ARW]

Deffo got 5V.

[ARW]

There is nothing worth losing on this PC. It's my second PC. I have a third PC availale for parts but it is so old that most of it is probably not compatible.

[Dave Plowman (News)]

I'd then remove all the cards like video etc and disconnect all drives. Leaving just the minimum on the motherboard. And see if it does the start up sequence. If not, try re-seating both the processor and memory. If still nothing, probably a dead motherboard.

[Matthias Czech]

Am 02.11.2013 16:38, schrieb ARW:

My mother's Acer (containig a similar mainbord) showed the same failure. Reason was a dead CMOS-Battery. (CR2032). Could not believe, that a weak cell can lead to such a behavior. So check the voltage of this battery. More than 3Volts are acceptable.

[polygonum]

That is what I was going to point at.

If machine has been lying around, mostly unused, and especially, not plugged in for long periods, the CMOS is a good bet.

Almost 100% not memory or hard drive as you should get a beep without either. However it is always possible that the beep itself is broken.

[Gefreiter Krueger]

If all that fails, reset the CMOS by shorting the two pins on the motherboard.

Or you could (if you think it's worth it) buy a tester card. I've got one (I think it was 20 quid). It plugs into PCI or ISA socket, and reads out numbers as the machine attempts to boot. Tells you what stage it's getting stuck at.

[Mr Pounder]

Can you not get safe mode? F8 on boot up.

[Brian Gaff]

Have you tried anothe psu?

How old is this machine?

Brian

[Brian Gaff]

I have an old one with a similar issue. It died one night while I was in the bath, so could not go and see what went wrong. came back to a dead psu, and a blown poer fuse. Replaced both and now the machine will act just as you describe most times when you turn it on, but if you leave the psu plugged in on standby for about a quarter of an hour before you press the on button, it bleeps and boots up. My feeling is that the original fault was a capacitor on the motherboard or a card going leaky, and now its sort of semi leaky so upsets the boot up. Leaving it on the capacitor gets less leaky and eventually there is enough voltage available to allow it to boot. Hard to trace such a fault though as swapping everything but the motherboard seems to make no difference, and the Moherboard has a forest of capacitors on it!

On another board, we have a noisy capacitor that puts clicks on the supply, I suspect its nearly time for it to to pop its clogs. Both machines are amd chipped motherboards, One is an Acer, the other some cheapo one from 2004.

Brian

[meow2222]

On Saturday, November 2, 2013 3:38:27 PM UTC, [e-mail] wr ote:

Wot people said. I've also had several do this due to bad caps on the mobo. They're replaceable if you can do basic electronics. ESR meter def recomme nded, £12 online.

NT

[D.M.Chapman]

I had the same on my Sons acer - if there is nothing (in terms of beeps) or BIOS output on the screen then I'd suggest PSU (if you are lucky it'll be standard and cheap) or the motherboard.

In my case it was the motherboard and the PSU was some nonstandard low profile thing grrrrr

Darren

[SteveW]

I'd certainly try a PSU swap. For a quick test, you can probably just put the two PCs side by side and swap the main power plug and CPU power plug over, with everything else disconnected on the faulty machine.

SteveW

[spuorgelgoog]

The voltages and connector is usually standard.

Gaffer tape the new PSU to the back of the PC. I did.

Owain