Computer randomly refusing to turn on

Ewaf · 1 Mar 2018 at 10:41

Hey chaps,

Recently, and completely randomly, my PC doesn't power on. I press the power button and nothing happens, zero signs of life at all. To fix it so far I've been unplugging the PSU and leaving a couple of mins, and trying again, rinsing and repeating and eventually it works. Obviously concerning though!

I have tried a different kettle lead, checked the power switch connectors, and all power connections inside. Is it the sign of my PSU on it's way out?

Thanks in advance!

MrRockliffe · 1 Mar 2018 at 10:52

Had a similar issue with mine, replaced PSU etc, turned out to be the power button on the case. See, if by pressing it a little harder, you can get it working

Ewaf · 1 Mar 2018 at 11:12

Didn't think to look at the actual button, just the connectors on the board. Will take a look and report back!

RJC · 1 Mar 2018 at 11:59

My old Corsair PSU started to do this, even linking the pins on the main ATX connector it refused to start on various occasions.

Habakkuk · 5 Mar 2018 at 00:54

You can get a external power switch to turn the computer on - give this a try to see if it's the case.

EsaT · 5 Mar 2018 at 10:05

Ewaf said:
Is it the sign of my PSU on it's way out?

So why you couldn't tell PC's components straight away?

But symptoms would fit pretty well to bad capacitors.

Habakkuk said:
You can get a external power switch to turn the computer on - give this a try to see if it's the case.

Using screwdriver to carefully short those two pins to which power button's cable is attached works as well.
Or switching cables of power and reset button.

Habakkuk · 8 Mar 2018 at 18:17

I cringe at the thought of shorting out a PSU by hand

mistersprinkles · 9 Mar 2018 at 05:45

EsaT said:
Using screwdriver to carefully short those two pins to which power button's cable is attached works as well.
Or switching cables of power and reset button.

This. Take an appropriately sized metal object and touch it to the two pins on the front panel header that are for the power switch. If it powers on every time you do this, your power button is shot. Otherwise its the PSU.

EsaT · 9 Mar 2018 at 09:12

Habakkuk said:
I cringe at the thought of shorting out a PSU by hand

Motherboard's pin header for power button is logic signal and not even connected to PSU.
Press of power button shorting those pins together tells electronics on motherboard (powered by 5V standby) to connect green wire pin of main ATX power cable to ground.
That's what starts and keeps PSU powered.

Admiral Huddy · 9 Mar 2018 at 09:30

try jumping the orange and any black cable on the PSU ATX connector.. then connect a single fan.. If this powers on then it may be the power switch is faulty on the case or the motherboard itself. Which ever, it eliminates the PSU.

https://forums.overclockers.co.uk/posts/19335172/