Question about liftmaster Chamberlain Garage Door Opener Transmitter 300MC

3 Answers

My liftmaster will not stay shut. I have spent hours trying to adjust the close, open forces and limits but to no avail. I will open fine but then when it goes to close it will go the floor and then pop open. Adjustments do not seem to make a difference. After mulitple trys it locks up and does not respond to remote or wall mount.

Posted by on

  • 3 more comments 
  • chandaelliot Apr 10, 2011

    the one sensor has a green light and I assume that is good. The other side is orange and I assume that is bad. I have a double door so the span is large. I have tried to "aim" the orange sensor to connect with the green sensor but it stays orange. Can it be a bad sensor? Can I turn the sensors off? Thanks.



    Mark Elliott

  • chandaelliot Apr 11, 2011

    I actually disconnected the sensors to see what happened and that shuts down the opener completely. I have been toying with the open and close adjustments and it has been very frustrating as I have only moved them a 1/4 turn at times to less than that. There are two sets of adjustments - one set is on the side that shows a + and - associated with two pictures, one of the doors opening and one closing. The other adjustments are on the back and they show something similar but say force and have weights as a measure. Is there some other adjustment I am missing?

    Thanks.



    Mark

  • chandaelliot Apr 12, 2011

    Just got home from work and looked at your feedback. I will check it all out and get back to you. Appreciate your help.

  • chandaelliot Apr 12, 2011

    The model or part number is 41AB050-2. It is a Liftmaster Professional Formula I. The width is 16ft. I took the one sensor that is orange and point it down to the ground and it shut the system down - when I put it back facing the other sensor it would allow for the door to shut. It is still orange. I cleaned and greased the tracks. The door does not run as smooth as it has there is a little hiccup as it comes up on one side which could be causing the problem but this has been going on for quite a while.

  • chandaelliot Apr 13, 2011

    yes. i also contacted liftmaster.

×

Ad

3 Answers

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Master
  • 710 Answers

Hi Chanda,

Liftmasters have a safety sensor near the floor on each side which will keep the door from closing should there be an obstruction, such as a rock, bike, or a child. This is government regulation.
In your user's manual there are instructions on how to adjust this if you have just installed it.

I think you would have noticed if there was something, even a rock, in the way. So, I looked on the LiftMaster website for troubleshooting advice on their doors. There are several ways to solve this problem. Here's the webaddress: http://www.liftmaster.com/consumerweb/service/faq

At that site you'll also find a customer service or contact link. If their suggestions don't work, get in touch with them.
If this webpage doesn't open up for you, please reply back and I will give you the information.

I hope this helps. If it does, I'd appreciate your vote or comment. Thanks for visiting fixya.com

Handie Andie

Posted on Apr 11, 2011

  • 2 more comments 
  • Handie Andie
    Handie Andie Apr 11, 2011

    Hi Mark,

    It sounds like the sensors are out of alignment. You're right, they have to see each other in order to function properly. Once you get them aligned, the orange should turn green.

    Handie Andie

  • Handie Andie
    Handie Andie Apr 11, 2011

    Mark,

    What is the model number of your liftmaster and the width of your door opening? I am contacting them to see what the max is on the width of the door.

    Handie Andie

  • Handie Andie
    Handie Andie Apr 13, 2011

    Hi Mark,
    I emailed them the problem and asked if the door opening was too large.
    Since you have the Professional model, I don't believe it is.
    Did you try adjusting the down force?

    Handie Andie

  • Handie Andie
    Handie Andie Apr 13, 2011

    Mark,
    Liftmaster said that the sensors are ok if they are both lit. They are yellow and green normally.

    Did you try to adjust the up and down force?

    Handie andie

×

Ad
  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    President:

    An expert whose answer got voted for 500 times.

  • Master
  • 2,468 Answers

Are the sensor eyes adjusted correctly??? if one eye is off as if it was bumped the unit will not operate correctly, near the door base are 2 eye-sensors,one eye is the beam eye(transmitter) and the other eye(receiver)if they cannot communicate(send beam/receive beam) it will perform poorly if at all,(CHECK ALL CONNECTIONS AS THESE CONNECTIONS TOO, IF FAULTY CAN DO THE SAME)

Posted on Apr 11, 2011

Ad
  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 2,510 Answers

There are sensors that have to see each other in order for the system to work. If the beam are not aligned, it will cause the door to go to the open position and it sounds like the sensors are out of alignment. When the door is closing, it moves a sensor slightly and this breaks the beam and the door reverses and opens. Work the sensors so that they are both aimed perfectly at each other. There may be an amber light that will change to a different color when the sensors are aligned.

Posted on Apr 10, 2011

  • 1 more comment 
  • Hans Pearson
    Hans Pearson Apr 11, 2011

    Morning Mark,
    Disabling the sensors will have the effect of blocking them off, and I think this will have the effect of running the door open. The sensors are there to prevent people/things being injured by a closing door. Evidently there are some couple mini dials on the machine which are used during installation to get the correct distance for closing and opening, they may be labled, but not all are. one is for open adjustment, and other is for close adjustment. They are very sensitive, even a slight adjustment translates to quite a large movement of the door. Generally adjust them a half turn at a time which is is equivalent to about 2" door movement. Try that - hope it helps.
    HANS

  • Hans Pearson
    Hans Pearson Apr 11, 2011

    The + and - adjustments would be the limit switches as you supposed and the other the froce which the door exerts before it opens again. I had an idea that the door would not work without the sensors. Had a similar problem on a Digidoor and it had overshot the limit switch. We had to manually get it back below that point to operate normally again. Fro what you say, it appears that your door limit switches are electronic rather than plain electric. There must be something that sends a signal to the box as to what the door position is and that must be the beams. I feel you need to keep working on the beams to sort out their alignment to get the door operational again, If that defies all attempts, there may be something faulty in the electronics.

  • Hans Pearson
    Hans Pearson Apr 12, 2011

    I have thought of some other problems that may be besetting you. If the door tracks are dirty or clogged with grease and dirt, especially molydenum based grease that has dried, it will load the doors additionally and may upset the force sensors on the doors control. Likewise, if the door channels are distorted or twisted, this would have the same affect. Set the doors to manual over ride and run them up and down by hand. They should move freely over their full travel without sticking or jerking. Also, the doors should stop where left at any poing on the channel, not tend to open or close on their own weight. If the counterbalance on the doors has become weak, it would place additional load on the drive mechanism, also upsetting the force sensors. If the door channels are gummed up. clean them thoroughly and relubiricate them with Door Lube Stick, not any graphite or moly grease which dries out.

×

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Liftmaster GDO goes up 1/2 way and stops,springs are fine.


The Liftmaster openers have 4 movement switches, a )opening and b) closing limit and c) opening and d) closing force. First check the door for smooth operation by opening the door by hand (disconnect from the opener with the release cord). Any binding should be felt this way. It is possible for a binding hinge, roller or torsion springs to add too much drag and cause the force switch to shut off the motor. Hinges, roller shafts and torsion springs should be lubricated at least annually with a non oily spray (silicone or teflon spray). Not WD-40 or 3-in-1! A light band of lube should be applied to the torsion spring coils. If the door can be operated smoothly by hand, then adjust the closing force switch 1/4 turn at a time. This is a safety device do not use it to overcome another problem!

Aug 15, 2014 | liftmaster Garage Door 1/2 Hp

1 Answer

Garage opener try to close door when door at close position


There are upper and lower limit settings, it sounds like you have the lower limit set to low. Adjust it so it stops the door as it contacts the floor and see if this solves the problem. It is possible these limit controls are damaged and will not stay set. If that is the case it may be best to replace the opener if you cannot find a replacement.

Apr 06, 2014 | liftmaster Chamberlain Garage Door Opener...

1 Answer

New Sears craftman 1/2 horsepower garage door opener not staying closed, trolley is hitting bolt stop and auto reversing.Have tried to adjust the down force and the distasnce down setting to no avail?


The 'down limit' on the side of the motor housing is what needs to be adjusted. Turn this control in the opposite direction of the arrow printed on the cover. I usually adjust this so it stops short by quite a bit and then fine tune it.

Oct 15, 2011 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Garage door will not stay down when closed


Sounds like the down limit is out of adjustment. Turn the Down limit switch opposite the direction of the arrow a quarter turn and try again. Repeat until the door stops before hitting the floor then fine tune to shut off at the floor.

Aug 14, 2011 | liftmaster Garage Door 1/2 Hp

1 Answer

Door reverses after fully closing, how do I determine if problem is due to adjustment to force or travel limits


If the door fully closes, the travel limit must be adjusted, as you suggested.
If the door were to open before fully closing, that would be too much rolling resistance.
Gary

Jul 12, 2011 | liftmaster Chamberlain Garage Door Opener...

1 Answer

I have Craftsman ½ HP Garage Door Opener Model 139.18458D. It reopens immediately after closing. Sometimes it works normally, and sometimes gives this problem. I have tried adjusting the close force,...


It sounds like the door is traveling too far in the down direction. When it hits the floor the safety causes it to reverse to the open position. You need to adjust the 'down limit' not the force.

Sep 06, 2010 | Sears Craftsman LiftMaster Chamberlain...

2 Answers

My Craftsman garage door opener opens fine. It


It could be closing too far or the sensitivity could be set too sensitive.

Lube the springs, wd-40 rust may be the whole problem.

If the door hits and the opener continues to move until the rail flexes upward and then reverses - probably the travel adjustment.

Does the door close and stay closed if you hold the wall button down constant until it closes? - this would indicate a safety eye problem.

If the door reverses before it hits the floor or just as it hits the floor it could be the sensitivity or if the safety eyes are mounted to the track they could be flexing enough to move the eyes out of alignment.

Hope this helps.


Jul 11, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Garage door closes and then automatically opens half way


ADJUST THE DOWN LIMIT IT THINKS THERE IS AN OBSTRUCTION AND IS REVERSING LIKE IT SHOULD.

TURN THE LIMIT ABOUT 1/4 TURN AT A TIME.

HOPE THIS HELPS

Mar 15, 2009 | Sears Craftsman LiftMaster Chamberlain...

4 Answers

Garage door won't stay closed


Check the down limit:
 If the light bulb(s) on your operator are on the front and/or back, the limit adjustment screw is on the left side of the operator (looking from the back of the operator and facing  the garage door).. If the lights are on the sides of the operator then the limit adjustment screw is on the left side (looking from the back of the operator and facing  the garage door)

Jan 03, 2009 | Electrical Supplies

2 Answers

Craftsman 1/2 hp door opener


replace the logic board
http://www.chamberlain-garage-door-openers.com/circuitboardcompatibilitychart.htm

Dec 16, 2007 | Sears Craftsman LiftMaster Chamberlain...

Not finding what you are looking for?
liftmaster Chamberlain Garage Door Opener Transmitter 300MC Logo

Related Topics:

1,764 people viewed this question

Ask a Question

Usually answered in minutes!

Top liftmaster Electrical Supplies Experts

Vince Heuser

Level 2 Expert

118 Answers

tamska1102

Level 1 Expert

28 Answers

ray gallant

Level 3 Expert

44268 Answers

Are you a liftmaster Electrical Supply Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...