On a flight after an annual inspection, the pilot could not retract the gear using the normal electrical system. It remained extended with the green safe light on and the gear pointer indicating down. He tried to assist the normal system with the manual handcrank, although the pilot handbook did not allow this practice, but to no avail. He then used the handcrank to move the gear to the extended position, but the green light would not reilluminate. The pilot elected to land on the dirt overrun area, but did not see a graded dirt bank short of the overrun. The gear hit the bank and collapsed during the landing. The landing gear circuit breaker was found in the 'popped' position. The normal and emergency gear systems had been checked during the annual inspection. The mechanic said that all breakers were in on the day before the flight. Reportedly, the pilot was unaware of a checklist item to assure all breakers were in before starting the engine. The investigation did not reveal when or why the landing gear circuit breaker got into the popped position.