If your Cayman won’t operate, you don’t hear a single beep when you deploy it, or two beeps when you retrieve it, it is most likely that the magnet in the magnet horseshoe has corroded away. If it has corroded out, it is simple to replace.  Order a new Magnetic Horseshoe for the following Cayman motors:

50700, 50718D, 507336, 50737, 50706