Sudden computer failure, not sure what the problem is

dirtydog

dirtydog

dirtydog

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My computer suddenly stopped working - I suspected the PSU but I swapped it for another one and there was no difference. The original PSU also worked fine in another machine so that is ruled out.

When you apply power to the board, there is a green LED which is constantly lit. When you press the power button, a red LED flickers on for half a second, and the CPU fan spins up for about one second - that's it - otherwise no sign of life whatsoever. No beeps, nothing.

Is the motherboard screwed or could it be something else? I also tried another CPU which is known good, and had the exact same result.

:/
 
Almost certainly motherboard.Bad RAM would give no display but the system should still power on.No other system component you haven't checked would cause the symptoms you've listed.

I diagnose a dead motherboard :D
 
Some more info - this is the sequence of events which resulted in the failure.

I turned on my TV which is connected to the graphics card via s-video lead, and the display was garbled which was unusual. I checked the lead was plugged into the TV and the card properly, which it was, but I then took it out and put it back into the graphics card. Maybe a mistake. It didn't solve the display problem.

I rebooted to see if that would fix it. I then got a 'cpu is unworkable and has been changed' message - so I checked the CPU BIOS settings, which were incorrectly set. I set them correctly (I think, in light of what happened next I can't say 100%), saved and rebooted. It did not boot, but gave an error beep - but the error beep I am quite sure was the display error beep, not CPU - they are distinctly different.

Okay I thought, I've buggered the graphics card. So I tried another one (known good) - exactly the same result. I then decided to reset the CMOS with the jumper. I did that, but afterwards ended up where I am now - an unresponsive board, no beeps, nothing. Just the LED to show it is receiving power, and the CPU fan spinning up briefly and then stopping.

I have ordered a new board but if anyone has any other ideas about fixing this one, please let me know.
 
Your GFX is OK as long as your TV is not faulty, and the card is actually screwed into the PC. Only a nasty voltage spike on the Svideo, or shaking the unsecured card in it's socket could cause it to break, and even then, you'd be very unlucky.
You haven't done anything daft with the CPU/RAM voltage have you?
Some boards will reset almost instantly if the CPU v is badly wrong.


Tried resetting CMOS?
 
I did try that :) When I adjusted the CPU settings, all I did was change the FSB and ratio back to what they should be. I never touched the voltage. It might not have booted because I failed to manually slacken the RAM timings; I remember before, the board defaults to setting tight timings which my RAM cannot boot with (ie. when the FSB is set to the correct level, ie. 200. At that time it had for some reason gone down to 100). But nonetheless, it shouldn't have done any harm, and a CMOS reset should have made the machine bootable again.
 
I fixed it - I have no idea quite how, but it is now fully working again :) I kept playing with it, took it all apart and re-assembled it all etc. and kept trying to clear the CMOS, and it worked. So that's saved me a few quid :D
 
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