Abstract: A poker or slot machine in which security is provided against tampering by monitoring the status of the reels of the machine and storing the status in a non-volatile memory. In the event of a power failure, the control unit of the machine tests the status of the reels upon power up and if the position of the reels is different to that indicated by the status held in the non-volatile memory, an alarm is initiated. If the status stored in the non-volatile memory indicates that a reel was spinning when just prior to the power failure, that reel will be respun upon power up. The control unit also monitors opening of the door providing access to the reel mechanism and causes the reels to respin whenever this door is closed.