The microswitch is mounted on the mainboard of the camera. The black actuating assembly slides across the microswitch and turns the camera on. There seems to be very few problems with the switch but a myriad of problems with the actuating assembly. The vent/actuating assembly is attached to the front case with silicone cement which does not bond to the plastic on the vent. In service, the constant pressure from the plungers and spring pushes
the assembly through the silicone into the camera body.
This causes the foot of the arm to hang on the micro switch body and break off the nib.
I have four (4) Stylus 300 here, one of which has been sent to Olympus for repair. Repair consists of replacing the front case half. The replacement case half contains an upgraded vent/link assembly which has heavier flanges and
a spring which extends over the case body. This replacement assembly SHOULD cure the recurrent failures.

Olympus refuses to sell the replacement parts and insists the camera be sent in for repair. Apparently the Japanese
consider the Americans too stupid to affect this repair! It is getting to the point that I would consider Americans stupid to keep buying products from this company. Any good camera repair facility should be capable or repairing one of these cameras in a few minutes if parts were made
available. These cameras can NOT be repaired without replacement parts! If an aftermarket supplier could be found to supply parts it would be a solution.