Pc randomly cutting out

My computer keeps randomly turning off. It can be anytime that it happens, no bluescreen or anything just off. It doesnt turn back on again untill as I (accidently) discovered you move the case slightly or knock it slightly.

This makes me think its a hardware problem rather than anything on the computer. My best guess was a loose connection but I cant find any anywhere. Could the power switch has a loose connection? The other thing I thought was a power supply issue. My psu is a 400w ocz stealthxtreme, and I have upgraded the computer since I bought that. Could it be the psu can no longer support the hardware in there?

Kitlist in my profile.

Any help would be appreciated.

Have you try using a wattage calculator.

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Originally Posted by cub1061

Have you try using a wattage calculator.

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Yeah my wattage comes out at 320w recommended. So I thought it'd be fine.

Although if I adjust capacitor aging it starts to go up. Although I'm not really sure what value to use for this?

Check for anything shorting the motherboard

depending on the PSU you can sometimes hear clicking sounds if the system tries to draw too much power - and when this happened to me I found some components kept working while others died.

Watch the LEDs on the motherboard/ethernet port. these tend to stay on even when the system is off but plugged in. When it turns off randomly if these go out (might take a minute or two) it's a safe bet the PSU is not supplying the motherboard with power anymore.

Also try disconnecting spare HDD + optical drives and see how the system runs with just the system drive operating.

cheers guys

Nothing shorting the motherboard that I can see.

Ethernet light goes off when it turns off. Also noticed when I checked it now that 2 of the fans are not working. There has been no warnings about this on the software. Guessing this means that the psu is not working very well/is being overloaded. Will try unplugging the other drives tomorrow and see if the fans run etc...

The case is clean so its not dust clogging the fans. Looks like a psu issue.

Any recommendations on a 600w or so psu? Nothing too expensive please!

how are the fans powered - from the motherboard or direct from PSU?

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Originally Posted by ik9000

how are the fans powered - from the motherboard or direct from PSU?

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Motherboard. The fan at the front of the case also running from the motherboard is working though. Have not checked the fan in the psu mind.

re PSU - this thread might help:

http://forums.hexus.net/hexus-hardwa...-getting.html?

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Originally Posted by no_numb

Motherboard. The fan at the front of the case also running from the motherboard is working though. Have not checked the fan in the psu mind.

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is it running from the same header or a different one?

ah actually not 100% sure if the front fan is on the motherboard tomorrow will check properly (in bed on the laptop). If its not on the motherboard does that mean its potentially a motherboard problem?

well if your MOBO is losing power, the fans powered from it won't be running either. If the fans running off the PSU keep running after the shut down and the MOBO has lost its power - then you're starting to narrow down where the problem lies. It could be as simple as the MOBO not having enough power due to the PSU not being able to supply it, or it could be a MOBO fault causing something to trip.

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Originally Posted by ik9000

well if your MOBO is losing power, the fans powered from it won't be running either. If the fans running off the PSU keep running after the shut down and the MOBO has lost its power - then you're starting to narrow down where the problem lies. It could be as simple as the MOBO not having enough power due to the PSU not being able to supply it, or it could be a MOBO fault causing something to trip.

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Sorry I should clarify the front fan does not stay on after shut down and the pc will not power back on till it is nudged. It appears that the 2 fans definately off the mobo do not run at all.

just noticed this system spec in SnootyJim's sig:

Desktop 2 (Self-built): 7 Home, CM RC-341, OCZ 400W XStream, GA-MA785GM-US2H, Phenom X4 9600 BE, 4GB RAM, 2TB HD204UI, 32GB OCZ Onyx SSD, HP w19

uses same PSU as you, and reasonably similar spec machine. He is complaining that the comp cuts out if he knocks it.... if his problem isn't the PSU then unless your PSU is faulty it should be able to power your rig. If his problem is the PSU then likelihood is yours is the root of your problem too.

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Originally Posted by no_numb

Sorry I should clarify the front fan does not stay on after shut down and the pc will not power back on till it is nudged. It appears that the 2 fans definately off the mobo do not run at all.

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when you say till it is nudged - do you mean turned on again or just given a hit? If everything's powering down it implies the PSU is either being overloaded + tripping, or else simply turning itself off to protect itself/the system, or lastly that it is receiving a shut-down signal from the MOBO to trick it into thinking that the machine is ready to be powered-down.

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Originally Posted by ik9000

when you say till it is nudged - do you mean turned on again or just given a hit? If everything's powering down it implies the PSU is either being overloaded + tripping, or else simply turning itself off to protect itself/the system, or lastly that it is receiving a shut-down signal from the MOBO to trick it into thinking that the machine is ready to be powered-down.

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Just given a hit, first found it out when I took the side panel off and it got a jolt and started working again. Untill it is knocked the power button does not work at all.

bizarre. you got another PSU around you can try (or know someone who does)?

Not easily unfortunately. Have a computer at my parents house I could take one out of to borrow but probs wont be there for a few weeks. Suppose I could wait as I've got my laptop to keep me going.

well I think I've fixed it. The was a problem with the pwm settings on the mobo not sure exactly what happened but the cpu fan was cutting out and I guess the cpu was overheating however none of the alarms/warning I set went off so I didnt know. Set the fan off pwm mode and just onto basic power and the problem has gone.

presume you're running a PWM fan with a 4-pin connector? If you just use a 3 pin fan off the PWM header you loose the PWM functionality and the system can need to be told this is the case in BIOS depending on the MOBO.

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Originally Posted by ik9000

presume you're running a PWM fan with a 4-pin connector? If you just use a 3 pin fan off the PWM header you loose the PWM functionality and the system can need to be told this is the case in BIOS depending on the MOBO.

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Yeah is a 4pin fan. Its quite strange as its been running for almost 2 years fine (well the fan/mobo combo other things have changed)

Problem is back!

Tempted to just upgrade the psu and see if that helps...

I had the same problem not long ago. I also have an OCZ StealthXtream (600w). I took everything out of the case and rebuilt naked on the desk and that fixed it. Possible case issue?

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Originally Posted by hotel2tango

I had the same problem not long ago. I also have an OCZ StealthXtream (600w). I took everything out of the case and rebuilt naked on the desk and that fixed it. Possible case issue?

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Sorted this a month or so ago but just to finalize the thread, took everything out and rebuilt and it worked. The case switch mobo header felt a bit dodgy but since rebuilding have had no problems.