On Monday, July 16, 2018 at 8:51:47 AM UTC-4, Wade Garrett wrote:
On 7/15/18 6:14 PM, GOM wrote:
Garage Door wont work. Motor €œgrinds€� but the chain/retracting cable
does not move. Unit is a Chamberlain security 1/2 horse power.

Are the door's counterweight springs intact?

If one or both failed, the unsprung weight of the door exceeds the
motor's lift capacity and it may grind- or just lock up.


Any ones made in at least the last several decades should trip, reverse, stop,
etc, but not grind because they have force sensors. Like others have said,
if the door is not freely moving and balanced it could cause the mechanism
to wear out prematurely, but it shouldn't cause it to not move and make
stripped gear noises.