PC won't boot but PSU seems active..

[basepointdesignz]

Hi,

My Girlfriend's son's computer died earlier today. I wasn't in at the time but he said he heard a crackle (but can't tell it was from the speakers or the pc itself) and windows froze and he reset the pc but it wouldn't work..

When i tested it, the heatsink fan was working, the psu seemed active, it 'sounded' (ie whirring and usually fan noises) like the computer was booting up as normal but i can't get anything from the graphics card to tell me what the hell is going on - i replaced the graphics card and still no picture. No beep to tell me that its even booting to BIOS..

I dunno if this means the mobo / processor is fried and dunno how i can tell..

Any ideas?

Cheers,

Paul
basepointdesignzltd..
XP Pro..
Pentium Core 2 Q6600 Quad Core
ASUS P5N-E SLI Motherboard
4GB DDR2 RAM
2 x SLI NVIDIA 8500GT SLi 1024MB DDR2 PCI-Express Graphics Cards

 

[Sephyr]

Same thing happened to me not too long ago. I had two 512 sticks of ram in there. I switched out each with an extra stick I had. Turned out one of the ones in my pc had died. Not really any rhyme or reason. Id try replacing the memory before jumping to processors and motherboards. cheaper to fix.

 

[G0AOZ]

Worth trying Sephyr's suggestion re the RAM.

The fact that you're getting no display might be a symptom of a faulty PSU. The PSU has several different output voltage rails, +12v, +5v, +3.3v etc. If one of these goes down or drops appreciably, then the machine won't fly. Try replacing the PSU with a known good one. Should be same wattage rating or higher.

ROGER - G0AOZ.

 

[paparazi]

What PSU is fitted? your setup is fairly power hungry and needs a quality PSU, 450watt minimum I would say, emphasis on quality, definately not the one that came with the case unless it's an Antec or similar brand.
Martin

On wings like angels whispers sweet
my heart it feels a broken beat
Touched soul and hurt lay wounded deep
Brown eyes are lost afar and sleep

 

[basepointdesignz]

But the fact that the psu is running and the blue light in it is on, plus both hard-drives are whirring and the cd drives are working (ie opening and the lights are blinking), also the processor fan runs, makes me think the psu is ok, but i'm no expert. Will try swappng psus and sorting out the ram..

I tried running the system with nothing attached to the mobo, only graphics card, then only sound but nothing, no beep or anything..

Cheers,

Paul
basepointdesignzltd..
XP Pro..
Pentium Core 2 Q6600 Quad Core
ASUS P5N-E SLI Motherboard
4GB DDR2 RAM
2 x SLI NVIDIA 8500GT SLi 1024MB DDR2 PCI-Express Graphics Cards

 

[BadBigBen]

makes me think the psu is ok, but i'm no expert.

that is exactly why G0AOZ pointed that out...

I've come across many PSU's that would deliver power to the FANs but not the mainboard, basically the 5v rail died and the other rails (-12v, 12v, 3v) where good...

so my money is on the PSU...

Ben

"If it works don't fix it! If it doesn't use a sledgehammer..."

 

[wahnula]

I wasn't in at the time but he said he heard a crackle

Hmmm...could have been a static discharge somewhere in the PC, or arcing of voltage...now where is the voltage high enough to create an arc and crackling??? The lowly PSU, and/or the (CRT) monitor. It could have been a dust bunny completing a path to ground, I hope it did not take anything else out with it.

Replace it with a known good only don't hook everything up that you don't have to. Blow it out with canned air (1/2 second bursts). No CD/DVDs, no USB, no peripherals, just the mainboard, CPU & 1 stick RAM. If no go, swap RAM sticks. That should get you to POST. Add the hard drive and boot. If you still can't get it to POST, try another graphics card and/or monitor. Best of luck.

Tony

Users helping Users...

 

[basepointdesignz]

Right, got somewhere today. Tried out an old psu, only 250w but thats the only one i have to hand and still nothing, but but but.....replacing the original psu (a relatively new jeantech 450w one), and removing just one ram stick, it booted to the bios but froze after about 30 seconds (couldn't arrow up or down on the keyboard (which is input as ps2, not usb))..

Then trying it agin, its back to the old symptoms (processor fan spinning, blue light on psu on and fan spinning, cd-drives blinking and hard-drive whirring but no picture on the screen and no computer beep)..

I could try after my holiday swapping the psu from my girlfriend's pc (which is a 700w'er) but until i'm stumped, but a si said i'm no expert and if you lot reckon it still could be the power unit, i'll try it out..



Cheers,

Paul
basepointdesignzltd..
XP Pro..
Pentium Core 2 Q6600 Quad Core
ASUS P5N-E SLI Motherboard
4GB DDR2 RAM
2 x SLI NVIDIA 8500GT SLi 1024MB DDR2 PCI-Express Graphics Cards

 

[wahnula]

...removing just one ram stick, it booted to the bios but froze after about 30 second

Then I would not remove the RAM from the list. You may have jarred something during your attempts that got a little reaction. Was everything else (CD, front USB, peripherals etc.) removed from the motherboard for your testing?

I would inspect the motherboard's capacitors as well, look for bulging at the top of the cap:

http://www.badcaps.net

Tony

Users helping Users...

 

[paparazi]

Yeah! possible but I reckon it's a bit new for bad caps.
I would strip back to bare bones as a first course of action, pull out/off everything including all front panel wires, addon cards (accept one graphics card) one stick of ram, no roms or floppy or HDD's
Clear the cmos (jumper?) see manual.
Use a small flat blade screwdriver to momentarily touch the pwr (power) header pins.
Go from there.
Add the boot drive first.
450watt Jeantech (known good) should be fine for testing a bare bone setup.
Martin

On wings like angels whispers sweet
my heart it feels a broken beat
Touched soul and hurt lay wounded deep
Brown eyes are lost afar and sleep

 

[wahnula]

Martin...the specs listed in basepointdesignz's signature are his personal rig, not the one in question (girlfriend's son's PC). We don't know what that is...or how new or old it is.

That information would not hurt though...

Tony

Users helping Users...

 

[hughejars]

From the sound of things here, somethings burnt out, most probably the CPU or something on the Motherboard. By reducing the power supply to a less powerful unit, the system would have used less power and taken longer to warm up than with a larger supply, which is why it booted momentarily. I recommend a few quid on new MB and CPU or even scavange a few second hand parts.
I have these Jeantech 450's in my systems, and so far (Touch wood) none have failed yet.
Let us know how you get on.

I'm studying hard every day, so why is the learning curve appear to be heading downwards?

 

[wahnula]

. By reducing the power supply to a less powerful unit, the system would have used less power and taken longer to warm up than with a larger supply, which is why it booted momentarily.

Sounds like sheer & utter speculation, but we do a lot of that here. Better guess might be a bad connection was arced long enough for it to work, but we don't have enough data to support either of these hypotheses. It would still be nice to have the specs of the problem PC, basepointdesignz.


Tony

Users helping Users...

 

[LawnBoy]

By reducing the power supply to a less powerful unit, the system would have used less power

I'm going one better than Tony and calling this utter bollox. The system will draw whatever power it needs and if the supply can't handle it then the supply shuts down. A supply does not dictate how much power a system needs, a system dictates how big a supply you must have.

No offense intented to the poster, but that's bad info.




--
The stagehand's axiom: "Never lift what you can drag, never drag what you can roll, never roll what you can leave.

 

[hughejars]

My this getting lairy.
Bottom line is you have to strip the system down and use a process of elimination in cases like these.
This person has already eliminated power supply and graphics card so surely now it's time move towards the MB and CPU, if you have concerns over the memory just try taking it out, it's not essential to booting.

I'm studying hard every day, so why is the learning curve appear to be heading downwards?

 

[fizzak]

Mobo is dead..Guaranteed.

 

[basepointdesignz]

Hi,

Sorry been on holiday so need to catch up.

The PC in question is a P4 2.4GHz, 1GB RAM, MSI motherboard (dunno what model), 450w Jeantech PSU - sorry for vagueness..

Right, when i got back, i tried my girlfriend's PSU (a 700w one) and still nothing - same symptoms - psu runs cooling fans but apart from that, its dead..

All of these tests have been done with all cd/dvd drives and harddrives removed from the power chain, only graphics card, mainboard and ram plugged-in / powered..

As fizzak said: 'Mobo is dead..Guaranteed.' So will invest in a new board and cpu. Do they still sell new P4s? or will i have to look around for a second-hander?




Cheers,

Paul
basepointdesignzltd..
XP Pro..
Pentium Core 2 Q6600 Quad Core
ASUS P5N-E SLI Motherboard
4GB DDR2 RAM
2 x SLI NVIDIA 8500GT SLi 1024MB DDR2 PCI-Express Graphics Cards

 

[wahnula]

Do they still sell new P4s? or will i have to look around for a second-hander

I would take this opportunity to upgrade the entire platform. Modern low-end (~$50) CPUs & mainboards absolutely blow away the old P4 platform. Get one with integrated graphics + 2GB DDR2 RAM for about $150.

Since you don't know if it's a CPU or mainboard fault (could be graphics as well) I would hesitate to throw good money at an old platform.

This plus this plus some RAM (2 of these) and you're set.

There comes a point in PC repair & upgrading where it's simply best to move on.

Tony

Users helping Users...