A slot machine is a machine that spins a series of mechanical reels and pays out credits when symbols line up on a pay line. While the original slot machine had five reels, later machines only had three, which made them simpler and more reliable. The pay table describes how many credits each symbol is worth, and the paytable is usually located on the face of the machine, above or below the area where the reels spin. If the machine has a help menu, the pay table will be listed there as well.

The first electromechanical slot machine was developed by Bally in 1963. While this type of machine was already in existence in the 1940s, it was not until Bally’s Money Honey machine that the industry began to see the full benefits of electromechanical construction. This machine was a big hit and featured a bottomless hopper and automatic payouts of up to 500 coins. Its popularity led to the gradual decline of side levers and made slot machines increasingly electronic.

The theoretical payout percentage of a slot machine is set at the factory when the software is written. However, if you want to change it, you must physically swap the software. This is a slow and expensive process because the software is stored on an EPROM. In addition, the EPROMs have a tamper-evident seal, so they can only be changed in the presence of Gaming Control Board officials.