Just refer to the solution below and follow some step by step procedures on how to diagnose the power switch problem
Samsung Note 3 SM N900 Power ON-OFF Switch Connection Tracks
Repair hints for Power Switch problem on Samsung Note 3 SM N900:
1. Check the power switch assembly, if the assembly is damaged replace the switch.
Sometimes even if the powerswitch is not not visually damaged, see to it that it still working by using a
2. For lifted button switch solder terminal pads on the PCB board, manage to re-establish the switch to its original position and bond it perfectly so that it won’t easily break. Then manage to reconnect the power switch line paths and the ground connection. If you can see an empty components solder pads just below of it, you can connect it to that spot. that is also connected to the power switch.