Maytag electric coin op dryer doesn't stop by timer.

Hi,
I have a electric Maytag coin-operated dryer. It runs perfectly. But it doesn’t stop by timer. It starts without inserting coin by pushing start button and I always hear small sound like a running machine/engine when I stop it manually opening the door.
Is there any way I can fix myself?

Rabi

Please help me to troubleshooting.