A security system for a gaming device prevents a door on the gaming device from being opened during a power failure so as to prevent tampering with the controls of the gaming device when no power is supplied to the system. When power is supplied to the system, a processor logs the time of occurrence of detected door openings in a nonerasable programmable memory so as to provide a record thereof. The information is stored in a sequential manner in accordance with the time of occurrence of the door opening events so that the microprocessor can verify the information stored. If any anomalies are detected in the stored information, the microprocessor 10 can prevent operation of the gaming device or generate alarms.