Diagnose the Mysterious Problem

Post by **Dalton** » 2006-03-03 10:24am

My brother's box won't boot. It's a computer I built for him a little while back, and it was working fine until just recently. Now it doesn't. When the power button is pressed, fans start spinning and things seem to be OK...but nothing happens. No POST, no BIOS, no Hard Drive spinning up, just an odd high-pitched whine.

Now the question is...fried motherboard, or fried proc? I do get a light on the mobo, but no BIOS and no POST.

Laughing Mechanicus · Post by **Laughing Mechanicus** » 2006-03-03 10:37am

This has happened to my machine when I tried to overclock it too far - the fact I couldn't get into the BIOS to undo the overclocking ofcourse made it very difficult to fix. Ofcourse if he wasn't toying with overclocking features this is unlikely.

The way I fixed it was by reseting the BIOS manually, the motherboard manual will tell you how to do this. It will likely mean either moving a jumper around while the system is powered down or possibly removing (waiting a short time, then reinserting) the battery on the motherboard that keeps the BIOS memory intact.

Ace Pace · Post by **Ace Pace** » 2006-03-03 10:44am

Aaron Ash wrote:This has happened to my machine when I tried to overclock it too far - the fact I couldn't get into the BIOS to undo the overclocking ofcourse made it very difficult to fix. Ofcourse if he wasn't toying with overclocking features this is unlikely.

The way I fixed it was by reseting the BIOS manually, the motherboard manual will tell you how to do this. It will likely mean either moving a jumper around while the system is powered down or possibly removing (waiting a short time, then reinserting) the battery on the motherboard that keeps the BIOS memory intact.

Taking out the battery will reset the BIOS, forcing you to reset time and all that.

Instant Sunrise · Post by **Instant Sunrise** » 2006-03-03 11:02am

I had a proc burn out on me when I was on a vacation.

If you look at the CPU itself, you should be able to see scorch marks around the various bits that stick out if it is cooked.

Batman · Post by **Batman** » 2006-03-03 11:03am

Ace Pace wrote: Taking out the battery will reset the BIOS, forcing you to reset time and all that.

That's the whole point of the operation, you know.

AA wrote: The way I fixed it was by reseting the BIOS

BIOS reset can't hurt. On top of that I'd remove all nonessential plug-in cards (so basically everything except the vid card), if that doesn't help the vid card, too, and on the off chance that one is available try another CPU.
Where's the whine coming from? Might be a broken/blocked fan somewhere.

Tiger Ace · Post by **Tiger Ace** » 2006-03-03 12:52pm

Batman, my point was just to add information, because some people are not aware system clocks are also BIOS dependent

Post by **Dalton** » 2006-03-03 12:56pm

Batman wrote:BIOS reset can't hurt. On top of that I'd remove all nonessential plug-in cards (so basically everything except the vid card), if that doesn't help the vid card, too, and on the off chance that one is available try another CPU.
Where's the whine coming from? Might be a broken/blocked fan somewhere.

I can't tell where the whine is coming from. I think the processor overheated though; it was an Athlon 2000+, as I recall, that tended to run very hot.

Vendetta · Post by **Vendetta** » 2006-03-03 01:02pm

There are a few steps to take:

1. Unplug the computer and hold the power circuit open by pressing and holding the power button for 5 seconds or so. (I find this works in about 5-10% of cases, it makes sure all the capacitors are drained).

2. Unplug all the PCI cards. If it works, plug them back in one by one.

3. Unplug and reseat the memory and CPU.

4. Unplug the memory and power the system on. If it doesn't beep, the CPU is fucked. If it beeps, it's probably the motherboard.

5. RMA whichever component proves faulty.

Uraniun235 · Post by **Uraniun235** » 2006-03-03 01:12pm

If the hard drives aren't even spinning up, then they're probably not getting power, and if that's the case then I'm betting it's the power supply.

4. Unplug the memory and power the system on. If it doesn't beep, the CPU is fucked. If it beeps, it's probably the motherboard.

Uh, that's not necessarily the case. I once managed to fry my memory and my motherboard, to the point where attempting to start the computer with no RAM in it elicited nothing but the fans spinning up, but when I gave the CPU to one of my friends (with the appropriate warning that it may or may not work) he later told me that it was working perfectly.

Instant Sunrise · Post by **Instant Sunrise** » 2006-03-03 05:26pm

Take the CPU fan off and look at the processor.

Athlons, if they overheat, will have burn marks on them.

If you are using the stock HSF, it is likely that the heatsink got clogged with dust, and the whine is the fan spinning but not moving any air.

namdoolb · Post by **namdoolb** » 2006-03-04 06:15am

I had a similar thing happen to me once, when I was fiddling around with the processor speed in the Bios. I set a speed that (unknown to me) the processor couldn't support. And what I got following that was pretty much what you describe.

I just had to trip the bios reset switch, and put all the settings back how they should be.

So that's another vote for Bios reset then.