Help with non-booting system Please!

P

PixPirate

Limp Gawd
Joined
Aug 18, 2005
Messages
144
I'm at my wits end and hope you guys can help. About a month ago my rig started having problems booting. It would power up, and a few seconds later power down. No BIOS screen. Fans and drives all spun up. However after repeating this cycle several times, it would come up.

I finally took it apart and found that one of the cheesy pushpins that hold the HSF on the CPU had come loose and therefore the 'contact patch' was very bad. Fixed that, but the problem kept getting worse. Finally it won't boot at all.

Symptoms: Hit the power switch. drives spin up, fans spin up, but no BIOS. And when I hit the reset button, it powers down(!) and then back up a few seconds later.

So I have:
Cleared the BIOS. No change.
Disconnected all drives. No change.
Replaced the 650W Antec power supply with a new 500W power supply. No change.
Removed all cards except video. No change.
Replaced the stock Intel HSF with a CoolerMaster MARS. No change.
Replaced the CPU (C2D 6700) with a Celeron-D 325 from another system. No change.
Removed the Video card (8800GTX) and replaced with old PCI video card. No change.
Replaced the MB (ASUS P5B Deluxe) with identical part. No change.
Removed the RAM. No change.
Disconnected all the USB/1394 ports and cables. No change.
Replaced the Power Supply AGAIN with a new Silverstone 850W unit. No change.

That's all I can think of! Anybody have ANY ideas no matter how crazy? I am going NUTS! There is nothing left to replace! Hope somebody has an idea!

TIA!
ThePP
 
What do you mean by "Removed the RAM. No change"?
Did you mean you replaced the ram with known good ram that has been tested in memtest86? Or you removed all the ram and tried to get it to post with no ram installed?
There must be something your overlooking being just about every part has been replaced.
Are you sure your monitor is in good working condition?
 
are you getting any error beeps or flashing led lights to let you know at what sequence the motherboard may not be responding?unplug mouse and keyboard to see if it locks-up if it makes it that far.have you total removed the motherboard from the case and put together outside the case ti see if there is a short?
 
try the following

take cover off your case and look for diagnostic LEDs for your mobo
look at your mannual to see if CPU, Mem and Video etc. are registering

Remove mem and see if you get a beep code.. usually three long beeps

replace video card if possible

replace PSU if possible. the system might be under powered due to a failing PSU.
 
Thanks for the replies:


There are 2 sticks of RAM, I removed one, tried to boot, put it back and removed the other, tried to boot, took out BOTH and tried to boot. No change in symptoms. Will a system POST with no memory? I've never tried....

There are no beeps at all. I think the MB has a speaker onboard so it should be able to beep if it wanted to! The ASUS logo on the MB lights up, which is normal behavoir, it's lit from the 5V standby power line, but at least I know that the MB is getting power. No flashing LEDs or anything like that.

Even though I tried it with a PCI video card, I'm gonna go buy a cheap video card at BB tonight and see if I get any change.

After that, I'll strip it out of the case and try it 'naked'. Some kind of short in the case is about the only thing left to check. Would it matter if the HSF is grounded to the case? The one I'm using has nuts on the back of the MB and they could be touching the MB tray. I would assume it would be OK for the HSF to be grounded, but maybe not. I'll put some tape on it and try again.

One thing that's going on that leads me to start suspecting the case is this: The case has some LEDs on the front for decoration; they plug into a 4-pin molex power connector. When that's plugged in, when I hit the power button, the PS comes on for just a flash and then shuts down and will not come back on till it's been unplugged and then plugged back in. Acts like there is a short. Hummm....
 
did your motherboard come with a d-bracket that has 4 led lights on it.if so look in users manual and hookup,then you should be able to trouble shoot.peace
 
PixPirate said:
Thanks for the replies:


Will a system POST with no memory? I've never tried....


A system without mem will not output to display i.e no screen... but you should hear beeps... the system should tell you three beeps or lights on board that mem is missing or not recongnised... I doubt this is the case for you however



One thing that's going on that leads me to start suspecting the case is this: The case has some LEDs on the front for decoration; they plug into a 4-pin molex power connector. When that's plugged in, when I hit the power button, the PS comes on for just a flash and then shuts down and will not come back on till it's been unplugged and then plugged back in. Acts like there is a short. Hummm....
Click to expand...


You are on the right track with suspecting a short... Its either that or a bad PSU... I would recommend unplugging everything but the mem and video card ( not even the hdd ) and try to boot... if that didn't work and it is possible to get your hands on a PSU ( you can buy one at bestbuy (30days return policy) to check it out .. just swap the 24 pin , 12v and any VGA connectors and try a cold start....

FInally if all else fails you can dismount the mobo and try it outside the case but ber very careful about ESD.. use an ESD wrist strap etc. when possible
 
Still no luck. I'm on my 3rd power supply, same symptoms. I've taken the MB out of the case, attached the video card and PS (and of course RAM and CPU and HSF), same exact thing.

I'm going to buy a THIRD motherboard today, I just can't imagine what's going on. Maybe the CPU and MB are toast. Getting ready to start throwing things!!

PP
 
hang in their man!

We have all been through this stuff in the past...

I once spend a whole week with two different motherboards and every single component replaced and in the end all I had to do was swap the placement on the memory modules a few times ( it never occured to me back then )

Anyways... just make sure you are handling the euipment carefully, I have fried montherboards before I even installed them, simply by holding them while wearing a wollen sweater, cotton socks on a persian carpet :) ( I am glad I didn't say that to the RMA rep when i sent that one back lolz )
 
Is this on an OC'd P5B? I had this exact same thing happen with a P5B Deluxe when I tried to push it too far on the OC. It kept doing the famous reboot loop until i pulled the power. Everyone should be aware that the P5b, when making changes in Bios, and you tell it to save, actually immediately powers completely down...then fires back up, then POSTS. I had never seen a board do this before, and it scared the crap out of me the first time. I thought I nuked the damned thing.

Moving on, when I attempted to OC the board too high, it did the power off, fire back up thing. Everything spun up, all the lights, the fans, etc. The off...then back on...over and over. Pressing reset or power just turned the system off. Here's what I did to fix it. Not all of this necessary, I would think...but I was pretty pissed.

1.) pull AC power from wall on PSU, switch PSU to OFF
2.) remove board from case
3.) remove RAM from board, remove video from board
4.) apply jumper to CMOS in "clear CMOS" position, and leave it there
5.) remove battery from board
6.) plug psu into board, make sure PSU switch is off
7.) replace BIOS battery on board
8.) set CMOS jumper to normal position
9.) test boot system with no RAM and no video. Make sure that if you do not have oboard system speaker, that you connect one. Listen fo beep codes, there should be some with no RAM and no video


If you get beep codes, put 1 stick of RAM and video card in the system. If it POSTS, add the second stick. If no beep codes...well...good luck with ASUS RMA...it takes over a month, usually.
 
That sounds exactly what's going on! THANKS! I'll try the fix as soon as I get home.

The system was not overclocked (other than the memory increased to 2.20v for stability), BUT the HSF has come partially loose (1 of the 4 pushpins popped out) and I'm wondering if the BIOS saw the high temp and decided to reset, and then got stuck in a loop?

We'll see. Thanks!

PP
 
Turned out to be a bad stick of memory. Serves me right for fixating on MB/PS and not fully testing the RAM. As soon as I pulled the bad stick out, all the problems went away.

Fry's is gonna hate me when I return all these parts....

Thanks all for your ideas.


PP
 
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