Computer powers on briefly even when unplugged

[codybrower]

I have an old computer that has always done something strange. After using it for some time, I can power it down, unplug it, and press the on button. At that point, everything will light up and the fans start, but only for about 1.5 seconds. Then it goes dead and acts like it should while unplugged (doing nothing). Any idea what component would cause this power storage? Is this the motherboard?

FYI - I have tried different power supplies, so I know it is not the PSU.

Thanks!

 

[velocityg4]

It's just a small amount of energy stored in the capacitors. That is not unusual. All PSU have capacitors. Capacitors take a little while to bleed off when unplugged. Which is why people are warned never to open up a PSU unless they know what they are doing. Even the motherboard has capacitors.