In a slot machine, the individual mechanical reels are stopped under the command of an electronic circuit at positions determined by a random count created by the electronic circuit. Specifically, counting registers are continuously cycled through counts corresponding to all possible combinations of the indicia on the reels at a rapid rate while the machine is idle, the cycling being stopped when play begins. The content of the registers at the moment when the cycling is stopped determines the position in which the electronic circuit will stop the reels. The randomness of the count may be increased by cyclically changing the relationship between the counting registers and the reels. The reel positions are delineated by a repeated code providing a different code for any successive three positions. Two sensors are provided to determine the position and detect an error in the stopped position of the reel.