Tip & How-To about liftmaster Chamberlain Garage Door Opener Transmitter 300MC
Place a 2x4 (or other object that is solid and about 2" thick)flat on the ground in the middle of the door. Activate the opener and lower the door until it makes contact with the 2x4. It should hit the 2x4 and then reverse in the upward direction. It can put pressure on the 2x4 just not stay there. If it reverses then it has passed. If it stays down then find the down force adjustment on the opener and turn it down. This adjustment can be found in your manual and will differ in location from brand to brand of garage door opener. Check the belt/chain for slack when it is running(there is no need to check this on a worm drive opener). If there is more than 3/4" slack then tighten it up with the tension adjuster on the trolley. Check the force adjustments per the manual as well. Do not pay attention to this slack when the door is shut as the trolley arm presses on the opener arm to gain the best seal at the bottom of the door. If you have a screw drive you can lubricate the screw with liquid graphite. All other types need none unless you want to lubricate the nylon gear inside the unit with rail grease, but be careful here and unplug the unit first. If your garage door opener has safety eyes start the door down and then cross the beam. The opener should reverse upward. If it does it passes, if not then call a reputable repair firm. Thanks BB
Posted by robert... on
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