[SOLVED] System turns on a few seconds when psu is off

coolraveen

Commendable
May 26, 2020
321
52
1,790
Hi I have a doubt, my computer is connected to a ups, and the psu switch in my pc was off, but when I pressed the power button the system turn on a few seconds and died,

Now after I switched on the smps, now my pc booted and worked normally.

Why did the system booted when the smps switch was off?, was it due to earth problem? Or bad power supply or board?

I then removed the pc from ups, and connected directly to the mains, and then grounded it by touching the cabinet, now the pc is not switching on when the smps is off
 
Solution
Best guess (and most likely), your PSU had enough power stored in it's capacitors to power on for milliseconds, hence why your PC turned on for a brief time.

Btw, the switch at the back of the PSU doesn't "turn off" the PSU. All it does, is cutting power connection between PSU and UPS/mains.

Aeacus

Polypheme
Ambassador
Best guess (and most likely), your PSU had enough power stored in it's capacitors to power on for milliseconds, hence why your PC turned on for a brief time.

Btw, the switch at the back of the PSU doesn't "turn off" the PSU. All it does, is cutting power connection between PSU and UPS/mains.
 
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Solution

coolraveen

Commendable
May 26, 2020
321
52
1,790
Best guess (and most likely), your PSU had enough power stored in it's capacitors to power on for milliseconds, hence why your PC turned on for a brief time.

Btw, the switch at the back of the PSU doesn't "turn off" the PSU. All it does, is cutting power connection between PSU and UPS/mains.
Thanks for your clarification bro, I found that your point is the right one.
 
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