Two weeks ago I had no experience at all with garage door openers other than clicking the button of my garage door remote to open and close the door, until one morning while clicking that button, the door started to act unexpectedly! The door would just travel a short distance then reverse back again. Even after disengaging the door lock, the trolley would still do that, moves for a few inches then reverse back without any blocks.
After calling several local technicians that have got some of the best reviews online, a couple of them visited my home taking a good amount of service call fees (I will come to that later) and suggesting solutions for hundreds of dollars without really having any clue about the real cause of the problem. Other technicians that I had to call several times, acted like celebrities, claiming that they have no time at all that week to come and fix my problem.
This experience pushed me to look into a solution myself, so I spent a weekend reading the opener manual carefully and searching online until I found a simple solution that costed me only a few dollars. More importantly, after this research I felt that I know about garage door openers and how they work more that the long-experience technicians I called. Some background, I am a Software Engineer myself in an area in California that has a lot of skillful software engineers but seems to lack of skillful technicians.
I decided to share this experience here with a two-fold goal: First, to help others like me who face similar problems to solve it themselves without going through all the pain. Second, to relieve some load from those super-busy technicians, so that hopefully they can do a better and sincere job for the few people who would still prefer to call them. In the following posts, I will talk about my experience with the technicians I have dealt with, then I will go into the problem and solution in more detail. I will also provide links and videos for some of the different problems that I came across while looking into this. The garage door opener I handled is a LiftMaster 3280, but many of these solutions apply to different models. No need to mention, these are just recommendations, do it at your own risk!