feed sensor on Staples SPL-TMC16A

I have a Staples SPL-TMC16A Shredder that runs fine however it will not stop running unless it powered off.

I believe the feeder sensor has gone bad.

I have the unit apart and both the sending and receiving sensor plug into the main power board.

1. Is there a way to test the sensors system?

2. Where can I find replacement parts?