Question about liftmaster Chamberlain Garage Door Opener Transmitter 300MC

2 Answers

Grage door reverces and goes back up after touching the ground

I hava a Lift master 1/2 hoursepower opner. After changing out the main drive gear the door will close but goes back up upon touching the ground. How do I fix this?

Posted by on

  • Thomas F. Schneider May 11, 2010

    Ajust the door so that it does not hit the floor so hard? Their is a limnit switch of some sort to stop it for going past a certain point. I am unsure which type it uses but if it goes past that point ,  it goes back up.

×

2 Answers

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that has over 10 points.

    Mayor:

    An expert whose answer got voted for 2 times.

  • Expert
  • 61 Answers

ADJUST THE CLOSE LIMIT SWITCH UNTIL THE DOOR CLOSE SOFTLY, UN CAN DECREASE IT BY TURNING THE FLAT SCREW COUNTERCLOCKWISE.... VERIFY THAT BOTH LEDS OF THE PHOTOCELLS ARE ONE.. OTHERWISE U GONNA HAVE TO ALIGN THEN OR REPLACE IT!

Posted on Mar 09, 2009

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

Try adjusting the close shut off switch.(limiting switch) It sounds like when the door shuts, it has too much pressure. The sensor picks this up and reverses the door.This is a saftey feature. It just needs adjusting

Posted on Mar 07, 2009

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:

5 Answers

I have a problem with a guardian 21230L garage door opener when you push the button the light flashes but no door movement happens can you help cheers Tom


I have the same problem. Door does not open or close when press the push button and/or transmitter. The light flashes 5 times. Manually open or close the door is ok. On the manual troubleshoot, it says it's either the opener is overheated or it's on vocation mode. I don't know how to switch of vocation mode. Is it possible the thermal sensor is broken?
Can someone help?

Jan 28, 2011 | liftmaster Electrical Supplies

1 Answer

WITH MY LIFT-MASTER DOWN FOR PARTS,I'VE BEEN USING THE MANUAL MODE UNHOOKING THE TROLLEY& LIFTING.I'VE USED THIS BEFORE WITH OUT MUCH EFFORT,NOW ITS REAL HEAVY.THE DOOR CLOSES UN-EVEN WITH RIGHT SIDE...


You are probably having either spring or lift cable troubles with the door since it is so heavy. A bad running door can strip the gears quicker than anything though. You will have to look inside the unit to see. Thanks BB

Sep 02, 2010 | liftmaster Chamberlain Garage Door Opener...

1 Answer

Help, my Lift-Master garage door opens 2-3 ft


SOUND LIKE A BROKEN SPRING.
LOOK ABOVE THE DOOR IF THERE IS A GAP IN THE SPRING IT NEEDS TO BE REPLACED,
I DO NOT RECOMEND THIS AS A DIY JOB. THEY ARE UNDER MUCH TENSION AND CAN COST YOU FINGERS IF YOU DON'T KNOW WHATYOU ARE DOING - CALL A PRO

HOPE THIS HELPS

Apr 10, 2010 | liftmaster Chamberlain Garage Door Opener...

1 Answer

The motor makes a noise but seems locked up. 2265R Chamberlain lift master professional 1/2 hp


Make sure the door is running well with out the openers help first of all. If it is making this sound then look inside the unit with the unit unplugged for white shavings. If so you will need to replace the gears. Thanks BB

Mar 30, 2010 | liftmaster Chamberlain Garage Door Opener...

1 Answer

How can iput the chain back on my lift master


Need lot more info. Did youtake it off. Did it fall off> Did you replace gears?

Oct 08, 2009 | liftmaster Chamberlain Garage Door Opener...

1 Answer

Door opner stops/appears to lose power


How old is your unit. I need to know this it sounds like a Circuit Board problem. but would have to know how old your unit is.

Apr 13, 2009 | liftmaster Chamberlain Garage Door Opener...

1 Answer

Lift-Master GDO goes up, not down


If the door operates freely without any binding, while operating it manually then It would appear that the obstruction sensor mounted across the doors path is ether out of alignment, lens dirty,or malfunctioning

Feb 21, 2009 | liftmaster Chamberlain Garage Door Opener...

1 Answer

Garage door goes a quarter way up.


If the wall station is flashing the lock button is on Push and hold the lock button for 2 sec. and release. The light should be solid(not flashing) For you door opening part of the way: If you have a Chraftsman/Liftmaster:
 1.Check to see if the door is running correctly.
  A. Run the door down and pull the emergency release. See if the door will run easily by itself.
    1. If it runs hard by hand try lubricating the rollers and hinges with silicone spray or some form of lubricant (not WD 40)
    2. If the door is heavy and falls back to the ground, you probably have a spring issue (either broken or needs more tension) in this case call a professional door repair company in your area.
  B. If the door runs fine then check the up and  down force on your operator (the box that hangs from the ceiling). If the light bulb(s) on your operator are on the front and/or back, the force adjustment screw is on the back of the operator. If the lights are on the sides of the operator then the force adjustment screw is on the right side (looking from the back of the operator and facing  the garage door). Turn the light blue adjustment screw with the up arrow to a higher number.
C. If this does not solve your problem the top bushing could be going out of your operator. Open the case and see if a lot of black filings are on the top of the big gear. If so the gear assy. will have to be replaced part # 41C4220A

Dec 09, 2008 | liftmaster Electrical Supplies

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

484 people viewed this question

Ask a Question

Usually answered in minutes!

Top liftmaster Electrical Supplies Experts

Mike

Level 3 Expert

4332 Answers

Gil Shultz

Level 3 Expert

3320 Answers

ray gallant

Level 3 Expert

37654 Answers

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

Answer questions

Manuals & User Guides

Loading...