[SOLVED] Is this normal? When power is switched on at wall socket, PC switches on then off briefly. Been told its a self-test?

Jan 25, 2022
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Hello

I've recently bought a new PC and the desktop powers up for a few seconds then goes off when the wall socket is switched on. I can then turn it on at the desktop power button and it runs ok.

I'm just concerned if this is actually a potential issue which could lead to real problems as time goes on? When querying it with the company I bought the PC from they stated the computer is doing a self-test to check all the components are working. Is this correct?

Thanks
 
The self test should only run when you turn it on, PC shouldn't turn on/off just by plugging it into the wall. That doesn't sound normal to me.
Then you're wrong.

If you cut power to the PSU, you cut power to the standby. Which a number of motherboard settings rely on to keep settings "remembered".

That said, the CMOS battery should maintain most of these setting. But I've found some BIOSs actually have a "feature" that makes the motherboard "test" the RAM with each cold boot (cold boot = turning the PSU off thus discontinuing +5VSB to the motherboard) and this will cause the board to "boot" a couple times before it actually POSTs.
 

Colif

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The self test should only run when you turn it on, PC shouldn't turn on/off just by plugging it into the wall. That doesn't sound normal to me.

Does the PSU have a switch on its back that you can use to turn it off? If so, I would use that before unplugging. it still shouldn't just turn on when that is flicked on. Switch on front of box should be only way it powers on at all.
 

Aeacus

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When querying it with the company I bought the PC from they stated the computer is doing a self-test to check all the components are working. Is this correct?
Only half-way.

Yes, there is power-on, self test, all PCs do, called POST. And it is done every time PC is powered on. However, never is included in the POST that PC shuts itself off after that. So, there must be something else wrong with PC.

Full system specs, including PSU make and model (or part number) is?
 
Hello

I've recently bought a new PC and the desktop powers up for a few seconds then goes off when the wall socket is switched on. I can then turn it on at the desktop power button and it runs ok.

I'm just concerned if this is actually a potential issue which could lead to real problems as time goes on? When querying it with the company I bought the PC from they stated the computer is doing a self-test to check all the components are working. Is this correct?

Thanks
Yes, If you're cutting power to the PSU, the +5VSB the motherboard needs to maintain some settings is lost.
 
The self test should only run when you turn it on, PC shouldn't turn on/off just by plugging it into the wall. That doesn't sound normal to me.
Then you're wrong.

If you cut power to the PSU, you cut power to the standby. Which a number of motherboard settings rely on to keep settings "remembered".

That said, the CMOS battery should maintain most of these setting. But I've found some BIOSs actually have a "feature" that makes the motherboard "test" the RAM with each cold boot (cold boot = turning the PSU off thus discontinuing +5VSB to the motherboard) and this will cause the board to "boot" a couple times before it actually POSTs.
 

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