PC only starts through motherboard

[Notacord]

My PC was working as normal but a few days ago it would not turn on unless I used the power button on the motherboard (Gigabyte Z77X-UD3H). The PC functions fine after it turns on but its annoying to have to open the case every time I need to use it.

I'm not sure what caused this problem as I hadn't opened the case in a few weeks. There was a short period of time (about 40 mins) where the CPU heated to 60-70 degrees Celsius because the fans didn't adjust properly, but I doubt that's the cause.

 

[ss202sl]

Power switch on the case? Check that the cables are connected. The switch may just have gone bad.

 

[tsnor]

If it starts with a MB button and not with the case switch then agree with prior post that the switch is probably disconnected or bad.

Here is how you test.

The power switch header on the MB has two pins. Find it's location and verify the power lead is plugged in. Then remove the power lead so you can get at the switch header.

The power on switch on a PC does not control power, it is just a momentary short to tell your motherboard's bios to power up or down. With the switch removed, and power on to the PC. and the PC plugged in at the wall use a screwdriver to short the two pins on the power header for just a second. The PC should start right up as though you pressed the power switch. If it does then try putting the power leads back on the header and seeing if the switch now works (it might, reseating the power lead might remove corrosion, etc.)

If the PC starts when you short the header and does not start with the switch then get a new switch. Google "ebay computer power switch" and take your pick of $4 to $10 parts. I've done this, worked fine. GL.

 

[Notacord]

If it starts with a MB button and not with the case switch then agree with prior post that the switch is probably disconnected or bad.

Here is how you test.

The power switch header on the MB has two pins. Find it's location and verify the power lead is plugged in. Then remove the power lead so you can get at the switch header.

The power on switch on a PC does not control power, it is just a momentary short to tell your motherboard's bios to power up or down. With the switch removed, and power on to the PC. and the PC plugged in at the wall use a screwdriver to short the two pins on the power header for just a second. The PC should start right up as though you pressed the power switch. If it does then try putting the power leads back on the header and seeing if the switch now works (it might, reseating the power lead might remove corrosion, etc.)

If the PC starts when you short the header and does not start with the switch then get a new switch. Google "ebay computer power switch" and take your pick of $4 to $10 parts. I've done this, worked fine. GL.

Thanks for the clear instructions and explanations. I think the problem was solved by reseating the power lead (as you suggested). I just have to press the button with slightly more force at a slightly different angle and the button works, thank you.

Thanks to ss202sl too, your help is appreciated.

 

[ss202sl]

I have one more thought about this. What about utilizing the reset button as a power on switch.

 

[Notacord]

I have one more thought about this. What about utilizing the reset button as a power on switch.

Huh, that's a neat little trick