PC problem - fault diagnosis

[al78]

A while ago my montior died (well, functioning but went blank) whilst I was using my PC. I have tried a number of things to try and diagnose the faulty component without much success. Here is a list of what I have tried:

1. If the monitor is plugged into the tower unit and both are switched on, the monitor will show a blank screen, the tower seems to function as normal. The green light initially comes on on the monitor but then goes to a flashing amber light (which normally occurs when the monitor is switched on and the tower unit is switched off). There are two possible places to plug in the signal cable, the graphics card or the integrated graphics on the motherboard. Both give the same result.

2. If the monitor is plugged into my laptop, the monitor works fine.

3. If the monitor is plugged in and switched on and the signal cable is disconnected, there is an on screen message "no signal cable detected, check signal cable".

Does anyone have any suggestions from this as to where the fault lies?

 

[fossyant]

Graphics card is probably dead.

Does the PC beep at all ?

If you can't see any of the boot messages, then it's the card.

Not the monitor as you can use it on a laptop.

How IT literate are you ? - Easy job to replace a graphics card, even if built in, you swap a jumper on the motherboard and install a new one (if inbuilt - maybe a bios option too) - if a 'card' it's a straight swap.....BUT........ Bit of faffing with drivers after a failure, but no big deal. Cost £50 max for a half decent one (cost varies from £20 to £400 or so - depends if you/kids play games.

 

[fossyant]

I'd also check inside and see if the graphics card is seated properly.

 

[Norm]

I'd also check inside and see if the graphics card is seated properly.

That would be the first thing I'd check. And I agree that, in the info given, it is not an issue with the monitor.

Does anything get displayed when you boot the tower? If it shows nothing, then it's a hardware problem, if it shows the BIOS screen, then it could be a driver problem.

IMO.

 

[al78]

Graphics card is probably dead.

Does the PC beep at all ?

If you can't see any of the boot messages, then it's the card.

Not the monitor as you can use it on a laptop.

How IT literate are you ? - Easy job to replace a graphics card, even if built in, you swap a jumper on the motherboard and install a new one (if inbuilt - maybe a bios option too) - if a 'card' it's a straight swap.....BUT........ Bit of faffing with drivers after a failure, but no big deal. Cost £50 max for a half decent one (cost varies from £20 to £400 or so - depends if you/kids play games.

I've just done another check on the tower unit and it does appear it is not functioning properly. The red disk activity light is permanently on so possible it could be a hard disk failure.

I am IT literate enough to be able to replace any faulty component myself, it is just diagnosing what has broken that is the tricky part at the moment.

 

[Norm]

Have it apart and (after grounding yourself on the chassis) check everything is seated properly. A loose card or memory chip will stop it in its tracks.

 

[rusky]

Dust on the DIMMS can cause this.

If reseating stuff doesn't work, disconnect it from the mains, take the CMOS battery out & short the terminals in the battery housing with a screwdriver or the likes.

Put the battery back in, go into the BIOS & select load optimised defaults. Save & exit (assuming you get to the BIOS!)

 

[al78]

further testing

Have checked all internal connections, all are fine.

This is getting weird. I have two hard drives and a DVDRW. Drive 1 is 200GB, drive 2 is 80GB. If I connect drive 1 only (i.e. disconnect the DVDRW and drive 2) then upon powering up the HDD light on the front of the tower does not light at all. If I connect drive 2 only then the HDD light is permanently lit. If I connect the DVDRW drive and drive 1 only (or DVDRW+drive 2 only) then the HDD light is permanently lit. In all cases the monitor remains blank and there are no beeps or anything to suggest the PC is going through the normal boot sequences.

FWIW if all drives are disconnected the monitor screen remains blank.

Could this be a motherboard fault?

P.S. I did make sure when swapping drives around that the master/slave jumpers were correctly positioned.

 

[rh100]

To trace a fault like this - i would disconnect everything inside that is not necessary. Disconnect all hard disk's and cd-rom drives from both power and data, remove any add on cards not needed. then switch on and see what happens.

Then do as rusky suggests with the dimms and bios - also try one or the other dimm on it's own if possible.

If you get it to start booting up - then start re-adding parts until it fails again.

 

[al78]

Still no luck unfortunately. Stripped it down to the point where the only things connected to the motherboard were the PSU, the switches at the front, the CPU fan and the DIMMS (tried removing switching them and replacing them - nothing). No joy.

It is a shame because the monitor, HDD and DVDRW are all useable so I am reluctant to throw it out. If the motherboard has failed then I will probably write it off and use my laptop instead, would be nice if I could give away the working components though.

 

[rusky]

What CPU is it? I may have a spare motherboard.

 

[rh100]

have you tried getting into BIOS - or is there nothing at all on screen?

to test any further - you may now need a spare psu, motherboard or cpu etc - so a difficult call. Are the fans running - ie the cpu fan? it may be worth checking the thermal compound on the cpu as it may be overheating.

 

[al78]

have you tried getting into BIOS - or is there nothing at all on screen?

to test any further - you may now need a spare psu, motherboard or cpu etc - so a difficult call. Are the fans running - ie the cpu fan? it may be worth checking the thermal compound on the cpu as it may be overheating.

No I cannot get anything on the screen, nor any beeps.

It looks like everything is powered up fine. The CPU fan runs, the led on the motherboard lights up when the power is on, everything that should light up does light up when the power is on.

The PC died whilst I was using it at the time, so it is not due to me doing any upgrading/fiddling about inside the case.

 

[al78]

What CPU is it? I may have a spare motherboard.

Celeron 2 GHz

 

[rusky]

Sorry, I was tired, what motherboard?