This document describes several methods that have been used to cheat slot machines, including:
1. Programming the machine at the factory to pay out on certain symbol combinations. This was successful until the perpetrators got greedy and got caught.
2. Using strings, wires, or metal tools inserted into the machine to trigger lever contacts and initiate payouts without coins being inserted. These methods took advantage of older mechanical designs.
3. Replacing the computer chip inside a machine to control payouts. One man made over $5 million using this method before machines were redesigned.
4. Exploiting software glitches, like one that caused wins to be doubled on a popular video poker machine.