Field guide

Software Chip Replacement (Ron Harris Method)

How it works

A highly technical cheat where an insider or technician replaces the machine’s EPROM or software chip with a modified version containing hidden backdoors or altered payout logic. The perpetrator accesses the machine’s logic board and swaps the original chip for a doctored one. The modified chip may contain a hidden software switch triggered by a specific sequence of button presses or coin insertions that guarantees a jackpot or overrides the RNG.

On the record

Nevada Gaming Control Board employee Ron Harris installed hidden software switches in specific machines during the early 1990s, controlling thirty machines and recruiting others to play them. The scheme resulted in hundreds of thousands in winnings before discovery.

Published as a detection reference for surveillance, compliance and gaming-operations professionals. Thresholds and tuning are set by the property. Nothing here is instruction — the method is described so it can be recognised.