Machine died whilst un-attended.

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Lan

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Well it seems to me that after a little time and troubleshooting you have answered your own question. You've narrowed it down to the CPU or MoBo. Are either of those two parts still in a warranty by chance? If so send them in. Or if not, then your cheapest bet would be to find a cheap MoBo and swap it out and see if that fixes it, in hopes that you won't need to buy another CPU.

Just my two cents.
 

Zoron

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Pull out the CPU and try turning it on again. If it powers up, then it's your CPU... if it doesn't, then it's most likely the motherboard. I'm more inclined to think at this point it is the mobo and not the CPU... but it could be both.
 

adrianxw

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Lan:

Since my last post, I have pulled the CPU out of this machine, and placed the "potentially faulty" CPU from the other machine in here. It ran. I stopped it at the BIOS screen, but everything looked fine, (I stopped it because the BIOS started saying "Hey new chip - let me change everything for you" type things which I didn't want).

I am sumising from this, that my CPU is still a CPU and not simply a stone/rock.

This leaves me with the MoBo or this sticky on/off switch business.

I'm urging away from the switch because the switch does seem to do something, whilst the MoBo does nothing.
 

Lan

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How long do the fans spin when you push the power button? a way to test the switch would be to swap the MoBo's cases, then try and run them both, and see what happens. Then you would isolate the switch and see if it is still a problem. Remember just because it does something doesn't mean the switch is working properly. I highly suggest checking it anyway, sometimes its only the simple things that we should check first.

Then, if it's not the switch, or the CPU it looks like you might have a fried MoBo. Try the case swap and post your results. I'm not really that busy at work today so I will probably be able to reply. :)
 

adrianxw

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Zoron:

Out of curiosity, I did try to power the system up without the CPU and nothing happened. Is that really a suprise though, I mean, the BIOS needs a processor to run it, or does it have a small processor of it's own? I don't know.

Anyway, the CPU from the dead machine runs when installed in this machine.
 

cowboytech

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hey, try this on your good machine. the next time you start it, instead of pushing and then letting go of the start button, push and hold the switch in, it should start to start, but since your holding the button in, it should be going through a 4 second count down to shut off, and in 4 seconds or so it should shut down
 

adrianxw

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Lan:

The Antec PSU's have 2 fans, a "puller" and a "pusher". The puller pulls air into the unit and is inside the case, the pusher exhausts warm air to the world - global warming. Normally the puller runs all the time, the pusher when the PSU internally detects heat problems. This arrangement keeps the noise levels down.

The "puller" is quite a hefty piece of kit. When pressing the button, it at most twitches, or turns maybe 1/4 round - never more.

When I had the older Sparkle PSU in there, the single fan started and stopped within a second.

The CPU fan is an altogether lighter affair, and varies between a "substantial twitch" to a "yee-ha" spin lasting perhaps a second, before chugging to a sighing halt. This could easily be capacitors holding enough charge to hold the rail up, or the generic lightness of the fan allowing a certain amount of variability.

Viz the switch, I can try pulling the leads off the head and shorting the pins with a bit of wire. I have yet to try this, but my wife is looking at 1) the dining room table covered with semi-disassembled machines, and 2) the steaming pot of chilli I am preparing, and making hungry "feed me" noises. This will have to wait until the morning.

I wish I had a job, a paying job I mean.
 

Anoobis

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Just attach your Mobo Power On/Off leads to the case's Reset Button instead of the Power Button. This will use the Reset Button as the Power On/Off button and will determine whether or not the actual Power On/Off button is the culprit (which I'm doubting).
 

mr_fnord

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It is possible for a bad CPU to damage a Mobo, but unlikely.

If you pull CPU does the PSU fan come on on power up? (Don't know if that works, just looking for a way to test Mobo)

If that doesn't work I would try moving the proc to a spare PC (not the only other one you own, if you can help it. ) I have never put a bad part into a PC and damaged the new machine, but I suppose it is possible...

I've seen one fried CPU in my life, but several bad Mobo's so based on that, my money is on the Mobo. The one bad CPU behaved as you describe, only no power up or fan on at all. Two PSU's later, it was the proc.

If you have not eliminated the power switch daughterboard try jumping it. It would suck to wait a week getting a new Mobo or proc to find out the $3 switch was killing you.
 

cowboytech

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when I have proven to myself, the only part left is the motherboard, I unplug the power supply from the wall, then I push the start button to clear residual power from the machine, I pull the mother board battery and carefully jump the motherboard battery terminals. Then I replace the battery, plug the machine back in and try starting it. if it doesnt work now, it is the board "or possibly a dip switch or mostly off jumper. The nightmares are the intermittent problems. PS find someway to enjoy the time you spend, its a mental thing, Life Goes On!
 

nobly

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You might consider that you have a dead BIOS chip. If its dead, basically nothing will happen - which seems to be your case.

Even if the power is applied w/o the CPU, it should beep an error code at you (I'm about 90% sure on that).

In any case, after you fix it, you might want to think about what caused the motherboard to die. Otherwise it might happen again. Typically its a power issue that makes a motherboard fry. They're quite resilent.
 

adrianxw

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Even if the power is applied w/o the CPU, it should beep an error code at you (I'm about 90% sure on that).
But what processor is running that program? I had always assumed the BIOS was simply an EAROM.
 

nobly

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I know there are beep codes for faulty CPUs. I assume that when it tries to use the CPU to launch the POST test, it can detect that the CPU is fried or broken, and then issue the error code. The first thing the POST does is check for power (heh) then check the CPU. If the CPU test fails, then it beeps.
If its not there... perhaps it won't, I'm not exactly sure.
 

Grimmy

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If the bios is working properly, it should beep, on hardware errors.

From the spreadsheet I did make on system beeps, a typical bios program should beep around 5 times, if it detects a faulty, or unseated (incorrectly installed) processor.
 

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