Solved pc starts then shuts down no POST

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May 25, 2012 at 17:40:27
Specs: windows VistHome Premiuma , 2.664 GHz
pc starts then shuts down no POST , I have unconnected everything from the mother board and taken the board out the case, it's now on a bench with only the cpu, cpu heatsink and fan plus the power supply connected, I short the 2 power switch pins with a screwdriver and it kicks up then shuts down 2 secs later with no beep so it's not even getting to POST

the pc is about 3 years old and hasn't had hardware issues before, nothing has been upgraded since built, the Mobo is an Asus M2N-SLI Deluxe cpu is an AMD and I think the size is 2.6Ghz I can't remember what the model is ie Athlon , the power supply is a Sumvision 450w P4, come to think about it the CMOS battery was replaced about a month ago with the right size 3v CR2032

theres 2 connections for the motherboard from the psu, 2x 4 pin connectors and the 20pin connector 1x 4 pin and the 20pin together and the other blue top left of the board so connectores have been taken out and re inserted to check they are not loose.

just covering everything I can there now for the question lol

what needs replacing? the motherboard, psu or cpu? , if it was mine I'd just build a new system but it's my dads.


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✔ Best Answer
May 27, 2012 at 02:53:49
sorted the easy way my dads decided to upgrade :) I took it to Maplins and they tried another psu and had the same problem, I took the heatsink and fan off the cpu and pulled the cpu out, cleaned it and put it back in and when turned on it stayed on, I then tried it a second time after cleaning it more and it switched off after a few seconds again so it must either be the cpu or the block that it sits in which is more likely

the case has been moved around quite a bit so the weight of the heatsink twisting the motherboard ever so slightly when the mobo is vertical at back of case might have stressed the connections? maybe? it's lasted him ages and rather than swapping out the mobo and cpu which is old ( found out single core 1600Ghz ) he's bought a new base unit and got a hell of a deal for it :)

Cheers



#1
May 25, 2012 at 17:42:03
oh also just remembered when it briefly kicks up the cpu fan does spin so nothing like not spinning so safely shuts down

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#2
May 25, 2012 at 21:47:14
I have an Asus mboard that's in the same series. M2N-E SLI.
The mboard manual is dated October 2006 .
Your mboard is about the same age.

The cpu fan must spin a reasonable speed when the mboard starts up, and it must be connected to the CPU fan header. If the bios detects no rpm, or an rpm below the minimum the bios expects, from the cpu fan header, the mboard will shut off automatically a short time after booting to prevent the cpu from burning out.

Make sure the connector from the cpu fan on the cpu fan header is not loose.

Side notes.
I'm still using the same AMD CPU (Athlon 64 X2 6000+) and fan / heat sink set that I bought when I bought the M2N-E SLI mboard, in a newer mboard. They have been used continously since then, in 3 mboards. The fan and CPU is still fine.
If the fan came with the heat sink and cpu in a AMD boxed set, there's probably nothing wrong with the fan. The fan would probably have an AMD label on it's blade.

A dead cmos battery, or even no cmos battery installed, cannot cause your symptoms.

It's extremely unlikely there's anything wrong
- with ram that worked fine in the same mboard previously
- with the cpu
- with the mboard

UNLESS some event has caused them to be damaged, such as a power failure event that produced power spikes or power surges, or a power supply has damaged them while the power supply was failing.

Power failure events often fry power supplies.

You get no video when there's no ram installed in the mboard, and the mboard will not boot all the way. If there were nothing else wrong, you would hear error beeps that indicate no ram is installed, if a case speaker or a piezo sound device is connected to the proper pins for a speaker on the mboard.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.

Other than that, the most likely thing is your power supply is in the process of failing.

You have an el-cheapo power supply.
Searching on the web finds it sells now for as little as 6.3 pounds (most of the "hits" are in the UK).

El-cheapo power supplies are a lot more likely to cause you problems.

Failing power supplies are common and can cause your symptoms.
Check your PS.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
See response 4 in this:
http://www.computing.net/hardware/w...

The only way to rule out the power supply as the cause of your problem FOR SURE without buying a new one is to try your power supply with another working computer, or try a power supply from a working computer with your computer, if you can.

If it is failing, you can usually replace it with any decent quality standard sized standard ATX PS with the same capacity or greater.

Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.

Don't buy an el-cheapo (in quality) PS.
See response 3 in this:
http://www.computing.net/answers/ha...

I no longer recommend Cooler Master, AOpen, or Sparkle power supplies.
I'm now downgrading Thermaltake to middle of the road.
Antec has two lines of PSs - the better line has a longer warranty for the same or similar capacity - the other line is more towards middle of the road.
AMD has a list of Certified (tested and found to be good quality) PSs:
http://support.amd.com/us/certified...

.......

Your mboard does not have onboard video.

What video card do you have installed ?

Your power supply must have at least the minimum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD ! )
If that info is not in the ad for the video card, you can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements. Some power supplies have two or more +12v ratings - in that case, add those ratings to determine the total +12v current capacity.

If you're a gamer...
In most if not all cases, the max capacity rating of the PS is an intermittent rating. It's recommended that you do not load your PS to any more that 80% of that rating if you are going to be using something that puts a constant load on it, such as playing a recent game for hours on end. In that case, you multiply the min capacity stated for the system with the particular video chipset on the card by 1.25 to find the min. capacity of the PS you should have.


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#3
May 26, 2012 at 03:37:40
wow that was lengthy thanks a lot buddy, yeah the psu is a cheap as chips one it was a bit more money when bought I think it was used for another older pc aswell so it might have been bought when they were top of the line way back in the day, I only have 1 other I can test it wih a 750w in my own pc but don't fancy taking that out it's a beast wired upto quite a bit in the case, I've got a friend that upgrades stuff it seems every other week so I'll ask him if he's got a spare psu.

thanks again fella.


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#4
May 27, 2012 at 02:53:49
✔ Best Answer
sorted the easy way my dads decided to upgrade :) I took it to Maplins and they tried another psu and had the same problem, I took the heatsink and fan off the cpu and pulled the cpu out, cleaned it and put it back in and when turned on it stayed on, I then tried it a second time after cleaning it more and it switched off after a few seconds again so it must either be the cpu or the block that it sits in which is more likely

the case has been moved around quite a bit so the weight of the heatsink twisting the motherboard ever so slightly when the mobo is vertical at back of case might have stressed the connections? maybe? it's lasted him ages and rather than swapping out the mobo and cpu which is old ( found out single core 1600Ghz ) he's bought a new base unit and got a hell of a deal for it :)

Cheers


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#5
May 27, 2012 at 06:49:39
Thanks for tying up this thread.

It's likely the el-cheapo PS damaged at least the mboard while failing.

It's foolish to buy an el-cheaspo PS.


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