If you're having slot problems in your casino, you're going to have to do some troubleshooting. Knowing all there is to know about slots is important for any casino or slot machine owner. This video will show you the trick to installing a coin into a coin comparator. One thing to remember, is that if there is no coin inside the comparitor, the machine will not work. And no matter what coin kind you have in the hopper, whether quarter, nickel, token, etc., it has to be the same coin inside the comparator, or you will have a malfunction in your slot machine. See how to install a coin into the comparitor.