Supermicro X11SCH keeps resetting - faulty power button?

[BoxTheBuilder]

I'm building a home fileserver with a X11SCH-LN4F board in an ancient Chenbro SR112 case. Everything works until I plug in the power button into the motherboard. I'm currently using the reset button as the power button

The system will power on and randomly restart, usually after a few seconds in the middle of post. This cycle repeats until I turn off the PSU or disconnect the power button.

The wires, header plug, switch, and joints visually look like they're still in good condition. Using a multimeter, I've confirmed that the button is behaving as expected (closed when pressed, open when up) and that the wires aren't shorted against the case.

The watchdog timer feature is disabled in the BIOS.

Is there some other cause that I've missed? This weirdness is making me think that I'm either going crazy or my hardware is haunted.

 

[pricklypunter]

Does the power button incorporate an LED? Going back some 20 years or so, I seem to remember encountering a similar problem, which turned out to be an LED wired in anti-parallel to the switch.

 

[BoxTheBuilder]

No LED, it's just a simple button.

 

[pricklypunter]

I guess, if you have a multimeter at hand, you could measure the voltage on the pins with the reset button connected and then the power button connected. If there's enough oxidation build up in the switch between the contacts, it might be mildly conductive, causing the voltage to hover right around the logic level threshold, any current draw on the power supply as things are starting up might tip it one way or the other. If you don't see any obvious difference in voltage, maybe try just hitting the switch with some contact cleaner and see if that helps

 

[RolloZ170]

X11SCH-LN4F board in an ancient Chenbro SR112 case

remove the board and check for mobo misplaced standoffs(shorting something)

 

[hmw]

I had this problem - turned out that my Seasonic Prime Titanium 750W PSU would randomly reset or power off - if I ran the system for days on end. It was always random and intermittent so hard to track down - I switched to another (Seasonic) PSU and it worked fine - try changing the PSU and check if this happens

 

[Sean Ho]

So if you disconnect the power switch and use a screwdriver to short the power-button pins on the front panel header on the motherboard, it turns on and stays on with no issues?

 

[RageBone]

dead and shorted out powerbutton. Happens.

 

[BoxTheBuilder]

I guess, if you have a multimeter at hand, you could measure the voltage on the pins with the reset button connected and then the power button connected. If there's enough oxidation build up in the switch between the contacts, it might be mildly conductive, causing the voltage to hover right around the logic level threshold, any current draw on the power supply as things are starting up might tip it one way or the other. If you don't see any obvious difference in voltage, maybe try just hitting the switch with some contact cleaner and see if that helps

Voltages look fine. I'll get some contact cleaner during the week and give it ago.

remove the board and check for mobo misplaced standoffs(shorting something)

Checked and re-checked for standoffs.

So if you disconnect the power switch and use a screwdriver to short the power-button pins on the front panel header on the motherboard, it turns on and stays on with no issues?

Yup, no issues using a screwdriver.

 

[RolloZ170]

Yup, no issues using a screwdriver.

pwr btn cable shorted by sharp sheet metal on the chassis/case ?

 

[RolloZ170]

and check for spycam's in your room...

 

[hmw]

and check for spycam's in your room...