Hi
Got this Envision monitor when press on/off switch have to press the switch many time before monitor will turn off,also have same problem to turn on monitor have to press on/off switch many time before monitor will come on.
I notice this switch is push button switch that does not have on/off look , like momentarily type push botton switch .
Is there some kind relay in the circuit when press the switch it make contact to turn on/off?
Enclosed is picture.

 

Those button type switches are not remarkably reliable. As it requires multiple presses both to turn on and off it is probably the switch itself which is faulty.