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

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When i press the control the door goes down about a foot and then comes back up and shuts off.I checked for obstructions on the sensors and did not find anything wrong

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If the main lights flash 10 times when the door reverses it is a door sensor problem. Make sure they are aligned and that the small light on each of them is lit and not flickering. If you can't get both lights to come on you most likely have a sensor that has failed.

If the main lights do not flash when the door reverses you most likely have a bad RPM sensor board. This is a small printed circuit board just in front of the motor and is what causes the door to reverse when it hits an obstacle.

You can also try increasing the down force adjustment which is on the rear of the motor unit near where all those white wires go. This will affect the safety reversing of the door so don't turn it too far.

Posted on Nov 13, 2009


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LiftMaster Pro 1/2 hp 41AS050-1 won't shut. when

Check the resistance down button (There is one for down and another one for up). You may need to adjust the sensitivity. That way even if for some reason the have hard time coming down, less sensitivity may solve that issue.

Oct 22, 2013 | Sears Craftsman LiftMaster Chamberlain...

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My garage door when closing goes down to about 1 foot from floor then goes back up. There is no obstruction. It will not go down to floor and stay down. HELP

There might not be an obstruction, but the opener THINKS there's an obstruction.
Check that there is nothing between the lenses of the two sensors. Even a spider web can trigger the safety.
If there is truly NOTHING obstructing the sensors' view of each other, then you should carefully re-align the sensors.
Also, make sure that all the screws and bolts on the rails are good and tight. As the door is used, bolts can loosen, which makes the rails start to vibrate and rattle during the door's movement. Eventually, all this vibration can make the sensors lose alignment.

Apr 29, 2011 | Electrical Supplies

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Hi I have a Chamberlain garage door system. I use the remote to shut the door. The door goes down to a foot off the ground and goes back up again. I've tried for over an hour to get it to shut and it won't...

The motor has probably been shut off by the thermal protector. Wait 15 to 20 minutes and it will reset itself.

If when the door reverses and goes back up, the main light flashes 10 times it is a door sensor problem. Make sure they are pointed at one another and the small light on each one is lit and not flickering. Tweak them a bit. If you cannot get both lights to come on you have a bad sensor.

Feb 18, 2011 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

The door comes down fully, and then goes back up. door will not fully shut. is there a way to adjust the down direction to get door to shut completely. There is no obstruction with the sensors.

If when the door reverses to the open position the main light flashes 10 times it is a door sensor problem. Make sure the sensors are pointed at one another and the small light on each one is lit and not flickering. Tweak them a bit. If you cannot get both lights to come on you have a bad sensor.

If this is not the case try releasing the door from the opener and operating by hand. Is there a point where it binds?

Feb 01, 2011 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Garage door goes up fine but when you press to come down it goes down one foot, seems like it hits something and returns.

There is a sensor which checks for obstructions, are you sure there is nothing impeding drive path?Inspect the drive path carefully. If it reaches a part of the drive path which causes it to slip or stick slightly this will tell it not to continue. Also but less likely have you checked that the optical sensor is clean and aligned. Make sure there is nothing blocking the optics.

Jan 17, 2011 | liftmaster Garage Door 1/2 Hp

1 Answer

Door goes down then comes back up and light flashes

Clear any obstruction from between the safety sensors. Loose leaves, trash, and dirt on the lens of the sensor itself are all examples of things that can obstruct the sensor's signal.

  1. Check each sensor for a steady glowing indicator light. If both indicator lights are on, or if one indicator light is flickering, the sensors may be slightly misaligned. To check for misalignment; obstruct the beam of the sensors so that they cannot see each other. When the beam is blocked, the indicator light on one of the two sensors will temporarily go out. This is the receiving sensor. Remove the obstruction and loosen the wing nut on the back of the receiving sensor. Adjust the receiving sensor until the green indicator light goes out, if not already out, then realign until the green light is bright and steady, then retighten the wing nut. This usually takes a couple of attempts before it is back in alignment.

  2. If an indicator light is out on one or both sensors, check for a possible loose or shorted wire. Sensor wires are attached to the white and black terminals on the back or side panel of the overhead motor unit. Check that they are securely connected to each terminal. Also check the wires for any breaks, especially anywhere they are spliced together.

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

1 Answer

Sears garage door opener troubleshooting yellow sensor light, what does it mean< how do I correct, door keeps reversing about a foot before closing completely

It is possible that there is an obstruction hitting the infrared beams causing the door to go back up. There should be a safety mechanism with sensors on each leg of the garage door track with and infrared beam (invisible to the eye) in case pets or children walk under the door when its closing so it will not crush them. Make sure the sensors are clear of obstructions, and check for objects stuck to the bottom of the door. When the door comes down a wet leaf stuck to the bottom of the door will hit the beam and signal it to go back up. Make sure the sensors are pointed at each other correctly ( they might have moved or been hit) and lastly there are settings on the head unit for travel and force. Travel will make doors move further down or up (distance wise) while force pushes or pulls the door up and down harder. Be careful if you adjust these settings, by doing it one at a time, with very little increments. I hope this helps and good luck!
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Nov 02, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

No matter where the door is located on the track when i engage it to the pully and press the button it will go down about 1 a foot and then stops and comes back up about 1 a foot and the lights blink....

There is an adjustment for how much 'torque' the unit is using to lower the door, and if your door is jamming or if this setting is set too low, the door will reverse. There are 4 adjustments on this unit: one for all the way up, one for all the way down, and the one for 'jams'
First: make sure you have BOTH a yellow light on one sensor and a green light on the other sensor. 2nd: Go inside the gararge (keep kids and pets away) and press and HOLD down the close/open button and keep holding it - this is an override for the photoeyes and your door should go all the way down to the close position. IF if doesn't, then you need to adjust the white knob that will allow it to close. It is testing to see if you have a jam, and the setting might be too low, or your door is binding. If these don't help, you'll have to call a pro. Good luck my friend.

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