Why does my opener only run for a short time then reverse?
I have a Craftsman garage door opener, 1/2 H.P., chain drive, Model #13953646 purchased in Novenber 1996. I came home from work one day and found white plastic dust on the garage floor directly beneath the opener. Obviously, something failed! I took it apart, and found the worm and drive gear destroyed (hence the white plastic dust). I replaced them with a kit from Sears. I have it sitting on my work bench (the entire opener) no load, chain not attached, limit switches opened up as much as possible, the safety obstruction eyes practicaly touching each other (green lights on both are steady)and when I activate the opener it only operates for about 5 revolutions in one direction, then reverses, and the green indicator light on the back of the unit blinks five times, stops blinking, then blinks five more times and so on. I can't figure out the problem!! Any suggestions?
Expert
Maestro
It sounds like you have all the safety systems that would reverse the door accounted for. Another item that might cause the same reversing after a short distance would be the RPM Sensor. The RPM Sensor is what the Logic Board uses to confirm the door is actually moving after it tells it to. If there is no RPM sensed then the Logic Board assumes some sort of problem has stopped the door and reverses it to prevent possible damages.
Look for a plastic cap on the end of the motor shaft that has some notches in it. This cap needs to be slid all the way onto the drive motor shaft so that the sensor can see changes as the notches pass it. If the cap is in place, check that the sensor and the wiring to it are okay and hooked up solidly.
The five flashes you are seeing is a diagnostic code for a problem with the RPM Sensor or Motor (see the link below for more details) so if the RPM sensor is okay then you might have a bad spot inside the motor itself or still have some binding in the drive and worm gears that overloads the motor.
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