liftmaster Chamberlain Garage Door Opener Transmitter 300MC "automatic goes down" Questions

goes down and pops back up. Hi, The adjustment is wrong...either there is something on the floor that it is hitting...frost has pushed up the floor a bit....or the adjustment is wrong up at the motor.

...down and shut off when the float goes up. What is the problem and how do I fix it? Hi, The switch goes bad and that happens sometimes... I guess you could change the switch but for the price of a new ...

...Automatic Doorman Model 455, problem is door goes down with no trouble, but lifting it goes about 10" and stops. I have changed the "V" belt, the problem still exists. I did an ampere ...

...goes on and the system works but I can not make it work automatic. Any ideas? Are you sure wiring is correct. If Line wires from breaker box are reversed, the clock motor does not get power, so clock ...

...goes off, i look out, does not seem to be running or maybe it was not sure, rain was slowing down so I silenced the alarm and went back to bed. In hindsight, I should have turned off the power. I was ...