Craftsman 3/4 HP chain-drive garage door openers?

Question

I was installing the garage door for my mom, and got everything installed except the sensors. I hooked them up and began adjusting the limits. I noticed the garage door  would go down and raise back up to about 5 ft.  and stop(this was because her old door was bowed inward and the door itself was breaking the sensor eye, but I didn't ralize that until it was too late). So I began adjusting the open limit until I over adjusted and when I  opened the door the trolley crashed back into the bumper bolt and now its frozen in the that position. 

I tried loosening the cable and chain and placing the trolley back to position the manual stated when I put it together but nothing seems to work.  I also thought about dry running the opener without the chain hooked up to at least let the motor reach its home position and then begin adjustments from that point. Sears wants to bend me over on the price of the service call and repair, so I'm hoping I can get a fresh set of ideas in order to get this problem fixed or I'm going to end up owing my mom a new opener...

John · Accepted Answer

Do NOT start in the middle and start adjusting unless you watch the limits and stop the motor when they are have way in between. I would do what your manual says, run the opener all the way closed, put chain back on and start again. since you jammed the carriage assembly against the stop bolt you may have to take a pair of vice grips on the shaft sticking out the front of the motor and give it a little turn - the motor probably locked up (happens ALL THE TIME with chamberlain openers). once motor runs - hook it all up. remember you moved the up limit too far so keep an eye on  it going up to shut it off and adjust the up limit before it jambs again. to get the door to close all the way you need to adjust the close force which should be near where you hooked the wires for the push button and sensors.you will see the numbers by those screws MOVE IT ONE NUMBER AT A TIME until it works the door properly. you definitely don't want too much pressure forcing the door or you may end up clasping a panel or more. if need to be adjust the open the same way so it opens correctly. be sure to oil your rollers pulley wheels and/or bearings with motor oil in a squirt can2-3 times a year to keep door running smoothly - the easier the door works the longer the opener will last.

Albert W · Answer

Hi There,
Your idea about "dry running" (without the trolley connected) sounds like the way to get starter.
Try to set everything "in the middle" and work both ways until you get things working.
Hope this helps,
Al

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Craftsman 3/4 HP chain-drive garage door openers?

2 Answers