When I pushed the button to open the garage door, I heard what sounded like a spark from the garage door opener as the motor started. At the same time, the circuit breaker clicked off and the door stopped. I turned the circuit breaker back on and the door worked, both up and down, but the light did not. I removed the light bulbs from the opener and checked them. They were OK, but there was no power coming to the light sockets. I'd appreciate any suggestions as to what the problem might be, what part to replace, etc. Thanks for your help.