Question about Sears Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+

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Only works on full down/up force

This is an older unit - pre door sensors
The opener will only travel a few inches and then stop - in either direction - even with the door disengaged unless I crank both force switches to max and then it seems to work fine but not the safest situation.
Any thoughts?

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Remove the cover from the motor unit and check the drive gear. This is sometimes an indication of a gear that is going bad. Your opener is around 20 years old and just maybe you should look at the new safer models.

Posted on Apr 30, 2010


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Have a chamberlain 132c2105-4 u it. Door moves up a few inches and down a few inches. Have played with limits and travel and sensitivities but can't get it to travel further. Help. Gordon

The chamberlain garage door openers have a label with the model number close to the light bulbs. The number you gave is the number of a label. Also, the "PART NO:" is just the receiver board part number.
Pull the cord to release the opener and check the full travel of the garage door. If it binds or catches, that might be stopping the opener from working. If that's not the problem, check the main gear by unplugging the opener and removing the shell. Then plug it back in and see if the gear contacting the worm gear on the motor shaft slips.That is the most likely worn part that needs replacing.

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My l/m door goes down but come right back up help

This can be one of two problems ! First problem can be that their is something blocking the infrared sensors that would cause the door to go back to the up position but in most cases if their is something blocking one of the sensors the door should not even move and just make a click sound and you will see the lights flashing on the garage door opener , it can also be a mis aligned sensor not pointing directly at the recieving sensor or vice versa! Ok if that was,nt the issue then you can make shure that the door isn,t traveling further then where it needs to stop to be closed, sometimes the chain or belt depending on your opener loosens up and can add an extra inch of travel to the door causing it to return to the up position, to fix this you have 2 adjustments on your opener ...1 will be a pressure adjustment can turn the adjustment to midway #6 to add some pressure so that the opener does not sense the xtra travel of the door , You can also backoff on the downtravel adjustment a turn or two and that will make the door not come down as far ...This adjustment is used to set how far the door goes up and how far you want the door to come down, you will see a picture of the door on both of these adjustments with an arrow letting you know which way to turn the screw ..remember each full turn of the screw equals 1/4" inch of travel to the door just follow the direction of the arrow or turn the screw counter clockwise for less travel !,,,Hope this helps you Sincerely Glenn

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No matter when i adjust the force the door goes down, stops briefely, them returns to open position. can't get force adjust to let it stay down.

If the door is hitting the floor and then reversing it is traveling too far in the down direction. Locate the 'down limit' on the side of the motor unit and turn it in the opposite direction of the arrow printed on the cover. Some tweaking of this control will be necessary to get the travel just right. The force adjustment affects the safety of your opener. Try to put it back where it was.

Sep 30, 2010 | Sears Craftsman LiftMaster Chamberlain...

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The opener seems to want to continue closing the door once it hits the ground. Seems like the closing mechanism needs to be adjusted back closer the the garage door closer unit. This did not just...

Try to re-program travel and force limits. Make sure that travel limit (down) does not go too far (thus excessive force). Apparently this system has a force sensor that senses if there is something in the way of the door. This is different from the safety sensor "eyes". The problem in your setup is that you have programmed the door to travel down too much and he system looses its ability to use force sensor. Adjust travel limit (down) to a little less travel and you will be fine.

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My craftsman 1/2 hp garage door starts to close and then opens up

I had a simular issue, except mine was that the previous owner decided to mess with all the settings and mounts and screwed everything up.

The problem isn't your force sensors its your downwards stopping sensor on the opposite side of the opener. For me I had to take the entire panel off and replace the sensor back in its holder, but try adjusting that sensor setting (clockwise goes down, counterclockwise goes up).

If that doesn't work then i dunno:)

Also set both force settings in between 0-1, for some reason with mine if i set it higher it would set them off....

Jul 19, 2009 | Sears Craftsman LiftMaster Chamberlain...

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Craftsman garage door opener won't close completely

look on the side of the openeer usually lekt looking at it from the rear theese are your travel adjusters one turn = 2" travel normally

Jan 07, 2009 | Sears Craftsman LiftMaster Chamberlain...

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There are adjustments on the unit itself that control the distance door travels to close as well as the force it uses to close. The info and location of controls is indicated in the manual that came with your unit.

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1 Answer

Opener will not reverse


Unplug power
Release the door from the opener close the door manually. take the chain loose and slide the traveler down to reengage with the trolley. Plug in power, run the unit with chain off untill it completes a clockwise cycle and stops. reconnect the chain and set tension.

Adjust the chain tension.

If it still moves 6-8 inches and flashes 5 times. the problem is in the rpm sensor.

Full diagnostics are in the owners manual - FREE at

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