Ah, okay, so it is literally a coin detector, not a coin acceptor (which detects if the correct coin is inserted before sending a signal). Thank you for the pictures and information.
The uC needs the crystal in order to properly operate. Removing it will not stop the time and probably have the uC perform strangely, if at all. Sorry.
The uC needs the crystal in order to properly operate. Removing it will not stop the time and probably have the uC perform strangely, if at all. Sorry.