One of our Craftsman garage door opener has recently started not always opening the whole way. It will come up to about five feet and stop. If we put it down and reverse it a few times, eventually it will go all the way up. This doesn't happen with every open, but it's frequent enough to be frustrating - probably 20% of lifts.

I adjusted the up force control to increase force, and that seemed to help but hasn't eliminated the problem. While I was up there, though, I noticed two things:

  • The belt for this opener seems to be significantly looser than the one on the other door bay. However, before a lift which fails, one side of the belt will be quite taut and the other slack.
  • The LED by the "learn" button is blinking: six blinks, then a pause (during which it flickers a bit), then six blinks, etc.. The manual says this probably indicates a logic board failure, because the status is meant to indicate a motor failure, and the logic board fails more often than the motor.

I'm relatively handy but I'm inexperienced with garage door openers. I'm relatively confident replacing the logic board (based on instructions I've read) but much less so troubleshooting the belt; I don't know where to start there. On the other hand, if the issue is the belt, replacing the logic board is unlikely to solve the problem (even if it's actually necessary).

How can I figure out if the problem is the belt or the logic board (or both)? (Subtext: should I keep at it myself or call a professional?)

  • Definitely, adjust the belt tensioning screw or bolt to get that taut, then unplug the unit for a minute to presumably clear any error codes. A loose belt can bind-up or slip & possibly cause an error code. If that still doesn't work & the Logic Board is considerably cheaper than a whole new unit, then replace it to hopefully find all problems gone.
    – Iggy
    Mar 1, 2016 at 2:49

1 Answer 1


Try disconnecting the door from the opener. Then you can open and close the door by hand to see if there is anything stuck or jammed. Could be that there is a kink in the track or one of the wheels is coming off the rail or something.

If door runs smoothly and without much effort then you can turn your attention to the opener. Note that it may be easier to just replace the whole unit; door openers are not that expensive. I certainly would not call a professional... a new opener is only $150 or so, you could easily blow through that with a diagnostic visit from a tech without actually getting to the real problem.

(If you have never disconnected the door before: there is usually a pull-cord or lever where the curved door arm meets the rail. Pull down to release the door, then push it back up to re-engage when you're done.)

  • Thanks! I happened to disconnect the door just before reading this: my wife came home and when she tried to put up the door the belt actually let go (didn't snap, but the bolt where it attaches to the trolley is now disconnected so something released). So I had to disconnect it to get the door open and then shut once she was in. It did run smoothly and without a lot of effort (I expected it to be heavier). I'll have to look into replacements or service for the opener.
    – pjmorse
    Mar 1, 2016 at 2:25

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