Pc Failure, not booting

peter999

Found this with google, this could be my problem:

Re: System Won't Boot - ATX Power Supply
http://newsgroups.derkeiler.com/Archive/Comp/comp.sys.ibm.pc.hardware.misc/2005-07/msg00026.html

Hi. I got a Socket 478 Northwood ATX motherboard that wouldn't startup with the normal Power On Self Test (POST) beep. The system would power up where the CPU fan starts, the HDDs spin up, the mobo LED lights up and the power supply fans all spin up. But the video would stay blank and there is no POST beep!

I've taken out everything from this system until I only had the video card installed and it still wouldn't POST. But it turns out the ATX power supply was the culprit. I temporarily replaced this one with another ATX power supply and it starts up normally. So I'm out $60 with and order to Newegg for a replacement.

Anybody had this problem before? Its bizarre that everything spins up and it turns out to be the power supply preventing proper system boot up. That threw me off for a couple of days as I thought maybe the video or memory was a problem. :-( I learn something new every time...

This could happen if the PSU does not assert the "power-good" signal.
Before this signal is active the mainboard will stay in a reset state,
since it cannot assume stable voltages from the PSU.
Arno

I think you're right. I've just read about the POWER_GOOD signal in Scott Mueller's "Upgrading and Repairing PCs" book. Its bizarre that that all the fans and lights are on though. I'll definitely be considering the the power supply the next time I encounter a system that suddenly stops to boot normally.

Also found this, didn't realise there is still power to motherboard, even though Pc not switched on via front switch.

ATX Power Supply
http://www.foxite.com/archives/atx-power-supply-0000193410.htm

... hit on in a round about way, is that with an ATX case and PSU, your main board is always powered.
So, if you`re going to go fiddling about inside, it is not enough to turn off your PC - you need to switch off the power at the wall socket. Otherwise you may (as I did when ATX first came out) blow your mobo.
Don`t pull the mains plug out of the wall - leave it in, but switched off. That way you still have Earth (Ground) reference for anti-static precautions.

I have been fiddling inside, so hope I haven't frazzled motherboard/components. Would leave earth lead connected & back switch was probably off, but didn't realise that if back switch was on, motherboard still got power, even though Pc not switched on with front switch & PSU fan not on.

peter999

peter999

I thought this was going to be staightforward.

I am not getting any POST boot beeps, nothing.

I have swapped processor, graphics card, memory, & even motherboard.
Checked monitor is working ok with laptop.

Finally thought it could be power supply, so swapped that.
None of the swaps seems to be making a difference.

Stil no boot, no message on screen, no POST beeps.

Any ideas what problem could be , what to try ??

peter999

gaming_guy

changing the power cable?

peter999

gaming_guy wrote: »

changing the power cable?

The CPU, power supply fans run & power gets to hard drive if plugged in when Pc switched on.

peter999

Pitchshifter

buy a new PC

peter999

peter999 wrote: »

I thought this was going to be staightforward.

I am not getting any POST boot beeps, nothing.

I have swapped processor, graphics card, memory, & even motherboard.
Checked monitor is working ok with laptop.

Finally thought it could be power supply, so swapped that.
None of the swaps seems to be making a difference.

Stil no boot, no message on screen, no POST beeps.

Any ideas what problem could be , what to try ??

Come on peeps give me some suggestions, I'm stuck.

Don't understand what's going on not get anything on screen, no BIOS screen before it reaches Windows, no POST boot fault beeps, absolutely nothing.

Don't understabnd what's going on, have tried swapping CPU, memory, graphics card, motherboard, monitor.

Can't pin down what the fault is !!

If initial BIOS screen does not display & no POST boot beeps, what fault can that point to, faulty motherboard, CPU, memory ??

peter999

jackthenipper

Sorry i don't have the answer either as i also have the same fault but i get 3 beeps on startup, i have also tried changing the cpu,ram,graphics card,processor & motherboard but all to no avail.

Have you ran the motherboard without any ram in & disconnected all 3rd party drives, so you only have the motherboard,graphics,cpu & processor with heat sync? Have you also plugged speakers in the rear of the board to check for a beep?

Please let me know how you get on as i will do the same.

gaz_jones

Believe it or not i too have a very similar problem. All of a sudden pc stopped giving out a signal to the screen. Stupid computers eh!! I dont get any beep codes to say what is wrong with it. Just simply wont boot up. Fans are running and hard drive running but thats about it.

aliEnRIK

peter999 wrote: »

Come on peeps give me some suggestions, I'm stuck.

Don't understand what's going on not get anything on screen, no BIOS screen before it reaches Windows, no POST boot fault beeps, absolutely nothing.

Don't understabnd what's going on, have tried swapping CPU, memory, graphics card, motherboard, monitor.

Can't pin down what the fault is !!

If initial BIOS screen does not display & no POST boot beeps, what fault can that point to, faulty motherboard, CPU, memory ??

peter999

So you changed motherboard but used same cpu?

Id guess cpu problem, but id try swopping ram with another computer first to see if its that or not

spakkker

Did you swap psu for a known working one or was it something that's "been in the loft for ages"?
I'd try mo/bo out of the case just psu monitor connected -with cpu and mem installed and see if it posts