Suggestions for a dead PC

[RustyPete]

One of my PCs played dead when I came back from holiday recently, it was working fine before I left & all I did before I went was shut down and unplug the mains. Everything else on the same circuit (2nd pc, router, printer etc) came back up ok.

This is a P4 running on an Asus P4B m/b. The only sign of life is the green standby LED on the motherboard. Everything else (PSU fan, processor fan, drives etc) is silent. Removing all peripherials, cards, memory etc one by one makes no difference.

How do I tell whether this is a dead PSU or dead m/b (there being nothing else left now)?

Any suggestions gratefully received.

Thanks,

Pete

 

[gcol]

I'd swap the psu for the one in the other pc and see if it worked first.

 

[LeeJC]

If the fan isn't rotating on switch on then 1 of 2 possibilties.

PSU is fudged as suggested.
Motherboard isnt telling PSU to switch on, check your pin headers to ensure your power on button header hasn't lifted itself.

To be totally honest i would bet on the motherboard not sending the on signal, if the psu fan isn't spinning then you are looking at a 12volt burn out, which would be quite smelly. And on Asus boards i believe the green LED is powered by the low current 12 volt line, don't quote me it could be the 5volt line.

The ATX powersupply conforming to standard has a grey wire which needs to be earthed by the motherboard to kick it into life, and it sounds like it isnt getting it.

I have had a dual asus which would do this on occasion, and found that by unplugging the mains connector until the green light extinguishes, it will sometimes spark back into life.

So in order

Unplug completely and let green light extinguish, then try and power on again.

Check power switch header for correct connection, while you are there and assuming your case has it, you can rule out the power switch by connecting the reset switch across the jumpers and trying to use that.

Do a bios reset, there is a jumper located in the area of the onboard battery, asus labels the jumpers quite well so look for something labelled batt or cmos it will be a header of 3 pins, with external power isolated, remove the header shift it so it is covering the middle and opposite pin to its original location leave for a couple of seconds and return to original position and try power on again. (bare in mind if this works the motherboard will have dropped all settings, date, time mem speed etc etc.)

Try the power supply on another machine, or borrow a replacement power supply from a friend and try that.

Hope you get it sorted mate.
Lee

 

[RustyPete]

Thanks for the advice Lee.

Been through the first of these steps and bypassed the front panel power switch - no change. Next I reset the bios. The result was that the processor fan gave a small kick first time round and then it all went back to being dead again.

Does this provide any more clues?

I can get a replacement PSU from a redundant machine at work so will go down this route next, but it may take to few days.

Cheers,

Pete

 

[RustyPete]

Just to close this one out guys, it was the PSU. Replaced it for £13 and now up & running with everything looking good.

Thanks for all the help.

Pete