This is a relatively new opener, we've only lived in this new build house a year and of course the opener is out of warranty. First it kept trying to drive itself when it was already down and wouldn't auto-reverse, instead it just tripped the breaker. Now it hums and won't move in any direction. I've detached the door and it rolls up and down fine. The slider part is so far down the track that you can't reattach the door.

I currently have it open and see no visual issues, no fried components on the logic board, capacitor looks okay, no broken gears, and when it's activated there is 0 movement. What should I try next? I'm off work for a surgery in 2 days, needless to say cash is tight.

Opener is a Chamberlain 8335W.

EDIT: I phoned Chamberlain today and they were more helpful than I thought! Over the phone they couldn't narrow it down so have sent me replacement parts for almost everything. Now the only thing is should I replace them all at once or try to narrow it down to whatever failed?

  • Chamberlain/liftmaster has world class customer support. Call them (800) 528-5880 they will talk to you for free, in or out of warranty. The advice may or may not be what you want to hear, but few companies offer the level of expertise regardless of age of your operator.
    – Tyson
    Feb 14, 2020 at 2:38

2 Answers 2


From personal experience, I suspect the logic board - but it's a nasty dice roll as the things are about half the cost of a new opener, and a new opener comes with a warranty, while a new logic board does not, and if I recall correctly was not returnable either, so if it does not solve the problem you're out that money. Mine had no visible damage.

In my case I was sure there had been a nearby lighting strike, and the opener did not stop altogether (so that's different from yours), but driving itself into the floor and not autoreversing were things it did after the event. Pay attention to the fact that these behaviors in an opener are things that kill people, particularly children (and pets) when counting the cost.

Then again, if money is tight, consider disconnecting the opener (well, you have already done that) and just operating the door manually until money is less tight. When you do repair or replace the opener, make sure it has a surge suppressor on the outlet.


It's really difficult to diagnose a garage door opener issue without seeing the door. There are a lot of pieces to consider and they typically need adjustments/maintenance on a regular basis. Some of the most common problems:

  • Rollers and rail guides loosen from vibrations of the door and throw off it's balance.
  • Opening and closing adjustment limits need to be recalibrated.
  • Closing force needs to be reset.
  • Electric eye is misaligned.

There are others as well. The point is that it's impossible to zero in on one thing.
My suggestions:
- Download the user manual if you don't already have it. - Check the rollers and rails to make sure all fasteners are snugged down.
- Check the down travel limit settings in the manual and adjust accordingly.
- Basically follow all of the instructions in the manual as if you were installing the door including making sure that the electric eyes are properly aligned.
All of this takes some patience but my guess is that this isn't a failed part but more than likely an alignment/recalibration issue.
If you still have the problem call Liftmaster customer service or a professional.

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