PC won't start

[DavidW]

I have what appears to be the identical problem reported recently by P4UL

In summary, a computer I built about 5 years ago (which has been fine until now) developed a fault about a month ago whereby when it is switched on, the fans start and the power & HD LEDs come on, and stay on, and nothing further happens.

The basics of the computer are: Intel P4 2.66GHz 478 socket/MSI motherboard/1GB (2x512MB) PC2100 RAM/Windows XP Home. On board audio & graphics are used, with no PCI boards attached.

My first instinct was a faulty motherboard, which I replaced with an ASRock P4i65G. Whilst replacing the board, I stripped the computer to give it a clean before re-assembly. It worked OK immediately, but this only lasted for about 2 weeks, when the fault returned.

I then thought it must the power supply, which had been jingled into temporary action whilst I was cleaning it. I replaced it with a Compucase Green Earth 350W (to help save the planet), but the fault is still there.

I have since tried everything I can think of: starting it after disconnecting all drives, front panel USB & audio, trying both RAM strips in DDR1 in turn (leaving DDR2 empty), testing the front panel switches & LEDs , rechecking all connections etc, but no joy.

The only thing I hadn’t done that was suggested in the P4UL threads was to remove & replace the motherboard battery with the power off. I did this, and now the fans come on as soon as the computer is plugged in, neither LED works, and the power switch does nothing at all!

Before I throw the beastly thing (and myself) into the canal, can anyone suggest anything I’ve missed? Could a faulty CPU be causing it?

[DirtyPolo]

Hello David and Welcome to Extreme Tech Support - Free PC Help!

 

When you took the system apart did you also take the CPU out? or leave it in the motherboard?

[DavidW]

PC won't start

 

I transferred the CPU from the original MSI board to the new ASRock one after the fault first appeared. I think this was done OK (cleaned surfaces with iso-propyl alcohol & used Artic Silver according to their instructions). Anyway, with the new motherboard the computer worked ok for about 2 weeks before the fault re-appeared.

[Tootech]

I think the best way to deal with this one is go back to basics.

 

There have been occasions when the underside of the board is close to the case and can touch the case causing some kind of short.

 

First thing to do is take out the board and check for that.

 

Whilst the board is out, remove the CMOS battery again and reset the CMOS using the jumper - check the manual for it position on the board. That makes sure it is reset. Refit the battery.

 

Refit the board, connect only the speaker and power button cabling to the Front Panel connectors

 

Take out the memory, leave it out for now.

 

Hook up your keyboard and mouse, video, power connector and 12V 4 pin connector.

 

Power on - what happens - does your board beep? It should do - its telling you it needs memory.

 

If so, plug in 1 memory stick and try again. It should boot and you will be able to get into the BIOS. If not, try the other stick of memory.

 

If it won't boot and just the fans come on then I would say that either your CPU has failed or your board is faulty.

[Jack Hackett]

5 years old eh.. hmmm

Replace the BIOS battery,this will most likely fix your issue

[DavidW]

PC won't start

 

Many thanks for the advice. I will give it a go & let you know what happens.

[DavidW]

PC won't start

 

Tootech

 

No go! I followed your advice to the letter, but with just speaker & power switch connected, its just the fans - no beep. The speaker is working, as I disconnected it & applied a voltage, and it beeped OK.

 

I have 2 concerns: The original fault (not booting, just fans & LEDs working, with the power button switching it on & off normally) happened with the original set up with the MSI board. The fault reappeared after I changed the board to the ASRock (albeit after a couple of weeks of normal operation). This seems to rule out the board as the cause, as it would be an incredible coincidence if the second board developed an identical fault to the first one. As I have also replaced the PSU, this seems to leave the CPU as culprit.

 

However, my second concern is what happened yesterday. I removed & replaced the BIOS battery (with the power off), and when I turned on the power, the fans immediately started (no LEDs), and the power switch has no effect. It would seem that the board is stuck in the power-on mode. It is still doing this today. Why should just removing & replacing the battery cause this? Weird! Have you come across this before, and is it repairable? I now seem to have a faulty board as well as a probably faulty CPU!

[Jack Hackett]

Did you replace the BIOS battery with a new one? or did you just remove and put back the one that was in it in the first place.

The suggestion to you was to replace with a NEW battery

 

be sure to fit it the correct way up, +positive upwards ;)

[DirtyPolo]

I doubt it will be a CMOS battery issue as you have replaced the mobo with a new one, asusming that you did not keep the old CMOS battery and fit it to the new board when you swapped?

 

Include that with the evidence that the machine worked for a few weeks before going again, shows that all is fine in the battery department.

[Plastic Nev]

Hi David,

From what you say in your first post, I suspect the PSU may well have been on the way out right at the beginning, hence the duff motherboard.

I am not sure what you mean by Jingling with the old PSU to get it to work? However it may have spiked again and now damaged your new motherboard before you got chance to replace the PSU with a new one.

It may cost a little to do so but is there a reliable tech in your area who can do a test on the board for you?

I do feel the bad news is your board has gone. The fact that only the fans work is a classic symptom.

[DavidW]

PC won't work

 

Jack Hackett – re BIOS battery: the current one is new, as it came with the new board

Plastic Nev – by “jiggling the PSU” I mean that by taking it out & cleaning it, it might have made it work properly again temporarily. I did not suspect the PSU until the fault came back after 2 weeks. I think you are correct when you say the old PSU has damaged the new board. That fits the facts.

I think it’s time to stop throwing good money after bad. The CPU is an old 478 socket, so I think I’ll spend £150 with eBuyer and upgrade to a modest Dual Core with new board & RAM, and give it another lease of life.

Many thanks for all your help.

[Dalo Harkin]

- just a note to this - I ALWAYS replace the standard jumpers with those from old HDD's/CDROMs

Alot of MOBO manufacturers fit some and they are not tight at all and cause lots of issues like you have described - they can just wobble lose by the slight vibrations of the PC.

If you can - check that the jumpers are tight as I have before now searched for ages looking for a fault that turned out to be this

[Jack Hackett]

Jack Hackett – re BIOS battery: the current one is new, as it came with the new board

 

So, it doesnt mean that the battery is new or good, it could have been sitting in the stores for a year or more before being fitted in the mobo. have you checked its voltage?

 

Even if it is new there could still be a motherboard problem that may cause the battery to drain prematurely so I recommend you get the multimeter out and test voltages.

Whilst you're at it check the voltages of the PSU

Driverheaven Guides: testing your psu with a multimeter

[Tootech]

I recommend you get the multimeter out and test voltages

 

Checking a battery with a meter will prove nothing.

 

A battery will often show full voltage when under no load i.e not drawing any current. It is only when the battery is in a loaded situation that it will show a drop off in performance.

 

Also, a flat CMOS battery would not exhibit the faults that are happening in this case.

 

Flat batteries with show as a something like 'BIOS Defaults Loaded Press F1 To Continue" messages, time and date errors and normally this will not happen when a computer is left switched on at the mains. Only when fully powered off.

 

A system will still boot with a flat CMOS battery.

[Dalo Harkin]

Checking a battery with a meter will prove nothing.

 

A battery will often show full voltage when under no load i.e not drawing any current. It is only when the battery is in a loaded situation that it will show a drop off in performance.

 

Also, a flat CMOS battery would not exhibit the faults that are happening in this case.

 

Flat batteries with show as a something like 'BIOS Defaults Loaded Press F1 To Continue" messages, time and date errors and normally this will not happen when a computer is left switched on at the mains. Only when fully powered off.

 

A system will still boot with a flat CMOS battery.

 

Agreed on all counts