[SOLVED] Weird PC Start-Up Phenomenon

[Atekkusu]

Last night I was playing League of Legends and in the middle of the game the shutdown loading screen appeared. I tried to reboot but the computer would only start for 3 seconds then immediately turned off. No sounds or beeps just brief lights and fan spins. I thought it was the power supply so I got a paper clip and jump started it and the fan kept spinning forever with no interruptions so I’d imagine that’s not the problem. I called it a night and today I tried to turn the computer on and it worked for 5 minutes and then displayed the shut down screen and turned off. I would think this would be a mobo short but would a short allow the computer to display the shut down screen and also allow it to start up again with time?

i also checked event viewer when I managed to turn it on today and it just said unexpected shutdown with no further explanation

I also read that the case plugs might have interfered so I unplugged all of them and manually tried to start the computer with the motherboard power button but nothing better happened.

It is to note though that when I press the “CMOS_SW” button next to the power button on the mobo or replug the power switch I can consistently get it to turn on for 3 seconds but when I press the power button (mobo button and case button) it only sometimes turns on with time. (If I spam the button it doesn’t work but if I wait it will)

 

[kerberos_20]

this sounds like power button is busted, if u disconnected front panel power button and it still does it, then button on mobo is bad

 

[Atekkusu]

this sounds like power button is busted, if u disconnected front panel power button and it still does it, then button on mobo is bad

the button still functions sometimes, and today I could keep the computer running for 5 minutes and then it would turn off by itself while also displaying the shut down screen.

 

[white.a.drew]

Last night I was playing League of Legends and in the middle of the game the shutdown loading screen appeared. I tried to reboot but the computer would only start for 3 seconds then immediately turned off. No sounds or beeps just brief lights and fan spins. I thought it was the power supply so I got a paper clip and jump started it and the fan kept spinning forever with no interruptions so I’d imagine that’s not the problem. I called it a night and today I tried to turn the computer on and it worked for 5 minutes and then displayed the shut down screen and turned off. I would think this would be a mobo short but would a short allow the computer to display the shut down screen and also allow it to start up again with time?

i also checked event viewer when I managed to turn it on today and it just said unexpected shutdown with no further explanation

I also read that the case plugs might have interfered so I unplugged all of them and manually tried to start the computer with the motherboard power button but nothing better happened.

It is to note though that when I press the “CMOS_SW” button next to the power button on the mobo or replug the power switch I can consistently get it to turn on for 3 seconds but when I press the power button (mobo button and case button) it only sometimes turns on with time. (If I spam the button it doesn’t work but if I wait it will)

Remove the CMOS

this sounds like power button is busted, if u disconnected front panel power button and it still does it, then button on mobo is bad

Can be but not 100% certain on that.. There are others things it can be
The button and switches and jumpers don't always clear the bios right. The only way to "properly" clear the bios.
Even with all of the way to do it the right way is
With the PSU unplugged pull the CMOS battery from the mobo and hold the power button for 30s x2s and reseat the CMOS battery and PSU cable try rebooting

 

[Atekkusu]

Remove the CMOS

Can be but not 100% certain on that.. There are others things it can be
The button and switches and jumpers don't always clear the bios right. The only way to "properly" clear the bios.
Even with all of the way to do it the right way is
With the PSU unplugged pull the CMOS battery from the mobo and hold the power button for 30s x2s and reseat the CMOS battery and PSU cable try rebooting

Ok, I removed the lithium battery and power supply cable, and held the mobo power button 2 times for 30 seconds and then reseated the battery. Same problem is happening... here’s a video:

View: https://youtu.be/u7qvwr7HY4w

 

[itsdigger]

This sounds very familiar to me . Even though you did the green wire test, it only shows that the fan runs. So what? What PSU are you using? I believe it is suspect...

 

[Atekkusu]

This sounds very familiar to me . Even though you did the green wire test, it only shows that the fan runs. So what? What PSU are you using? I believe it is suspect...

EVGA 850 G2 Supernova. That’s interesting.... even if the fan runs that doesn’t mean the PSU is good?

 

[itsdigger]

No, that's not proof that the PSU is good BUT, this is a high quality psu so I believe we can rule it out...

 

[Atekkusu]

No, that's not proof that the PSU is good BUT, this is a high quality psu so I believe we can rule it out...

Yeah so this means it’s a shorted motherboard? I just find it hard to believe because I managed to get it working today and when it turned off it displayed the shutting down screen. I’d imagine if something loses electricity it would instantly stop....

 

[itsdigger]

This thing is going to be stubborn so here we go!

Take it apart and put it together, outside of the case with the bare minimum of parts on a piece of cardboard and start ruling things out....

 

[white.a.drew]

Last night I was playing League of Legends and in the middle of the game the shutdown loading screen appeared. I tried to reboot but the computer would only start for 3 seconds then immediately turned off. No sounds or beeps just brief lights and fan spins. I thought it was the power supply so I got a paper clip and jump started it and the fan kept spinning forever with no interruptions so I’d imagine that’s not the problem. I called it a night and today I tried to turn the computer on and it worked for 5 minutes and then displayed the shut down screen and turned off. I would think this would be a mobo short but would a short allow the computer to display the shut down screen and also allow it to start up again with time?

i also checked event viewer when I managed to turn it on today and it just said unexpected shutdown with no further explanation

I also read that the case plugs might have interfered so I unplugged all of them and manually tried to start the computer with the motherboard power button but nothing better happened.

It is to note though that when I press the “CMOS_SW” button next to the power button on the mobo or replug the power switch I can consistently get it to turn on for 3 seconds but when I press the power button (mobo button and case button) it only sometimes turns on with time. (If I spam the button it doesn’t work but if I wait it will)

How old is this system? I think I may have you problem. Especially if it's the mobo I think it is full speccs?