Continual shutdown cycling

[Number6]

I'm assuming this is a power supply related issue but I thought I'd ask here before committing.

 

I have a PC that, when switched on almost immediately shuts down again. Sometimes it gets as far as the POST screen but usually not even that far. I've removed all the cards and swapped the RAM to no avail.

 

Power supply?

 

Or has anyone else experienced this and found a different cause?

[imiddleton25]

check that the fan on the cpu is working and that the heatsink is clean from dust, also check power supply fan is working as i have had a supply with fan not working had similiar problems.

[ranj]

Either power supply or CPU fan not working. Depending on your BIOS it may give you a message and it may say "CPU fan error" if you have a similar error appear it would indicate its a problems with the CPU.

[Number6]

check that the fan on the cpu is working and that the heatsink is clean from dust, also check power supply fan is working as i have had a supply with fan not working had similiar problems.

 

All fans are working and clean.

 

I forgot to add in my original post that when it shuts down it immediately tries to restart and keeps cycling for 10 or so times then shuts down altogether. Hit the power buton and the cycle starts all over again.

[Messa]

I Had this with a dell machine, turned out to be motherboard.. might be worth a look..

[PeterW]

check that the fan on the cpu is working and that the heatsink is clean from dust,

 

Would second this.

[FN-GM]

Remove all drives inc HDD and see if it does the same.

[Number6]

I've now tried disconnecting everything including the CPU fan and the behaviour remains the same. System powers up and within 5 seconds it turns off again, screen doesn't even so much as light up so no info there.

 

Puzzling.

[FN-GM]

Do you hear any beeping?

[p858snake]

Try a different cpu with the motherboard if possible, i had the same issue when my motherboard and cpu broke.

[Michael]

Try re-seating the processor. I had a customer with a similar problem recently. When they turned their computer tower style it stopped working, but when lying flat it did work.

[Willott]

Do you notice the PSU fan stopping and starting when it reboots (ie is it doing full power off then back on), or anything else to suggest full power cycle rather than soft? If it does, and you are technically and electrically competent (covering my rear end!), and you are willing to take the risk yourself, you could try shorting pins on the atx power lead to see whether the PSU runs fine on it's own. A quick google search will show you how, I have done several times, and am still alive/uninjured from doing so. The other option is to swap the PSU out with another, and test that way (I'd suggest sticking the problem PSU in another system, but if there's a problem with it, it may cause some damage to the other system).

 

My first instincts would say the PSU isn't the problem. If you remove all components from the motherboard, including front panel connectors (just leave power and speaker connected), then build up from there through the POST beeps, you may be able to determine what is causing the issue.

[jamesb]

Check whether there's anything shorting the USB ports on the motherboard.