November 22, 2008
The STB sensor signal is ok, but the opener still acts as though its obstructed and the door reverses. What can I check?
It is a Craftsman 1/2 HP opener, model 139.536228SR, serial 09544B01071. The wiring appears to be correct. The (2) whites to "2" and (2) white/blacks to "3". The wall mount is correctly wired. The sensor signal remains solid green even when blocking/obstructing the signal path.
Jimmy k
Expert
The green led is the sender and will remain solid when the signal is blocked. The amber led should blink when it doesn't receive the signal.
Check the voltage at the sensors and at terminal 2 and 3 on the opener. It should be 4-5 volts dc at both locations. This will eliminate the logic board of the opener and the wires to the sensors.Watch the amber led while the door is going down. If it never blinks and the door reverses, the sensors should be replaced. Sometimes the rail on the door will flex and move while the door is opening and closing. This can cause the sensors to move out of alignment and reverse the door.If you have further questions after these tests, send another email and we will try to help you.Join this conversation.
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