To troubleshoot this state, remove the circuit board from the case to get access to the top of the board, with the CPU, fan, power switch, etc.

Inspect for damage or contamination such as liquid leaking through the power button

Possible Switch issue

• Power to the device (circuit board LEDs light, USB devices get power), but pressing the power switch does light the power light or turn on the CPU fam

Try:

• Clean the switch using electronics contact cleaner - YouTube video ecologicaltime - Intel NUC not turning on - disassembly and fault tracing - faulty switch

Missing content:

• multimeter tests
• is the power module reparable?
• is the switch reparable?