Is the "trolley" that moves back and forth jammed against something?

By trolley I guess you mean a metal strip at the end of the chain that moves on the rail. It is at the extreme position close to the opener, pressing against a bolt that I guess is designed to stop it from moving any closer to the opener. I did get the feeling that it was pressing hard against it.

I also notiiced that this happens during the winter. Some contraction may be causing it.

Remove that bolt and the door should then close. On the side of the motor unit you will find a control labeled 'up limit'. Turn this about 3 times in the opposite direction of the arrow printed on the cover and it should take care of your problem. Be sure to replace that bolt.

"It is at the extreme position close to the opener, pressing against a bolt that I guess is designed to stop it from moving any closer to the opener."

Based on the symptoms of humming and no motion that is the condition I expected it to be in.

However, in your original post you wrote: ...when I pressed the button to open the door, the opener hummed but did nothing.

When you open the door the trolley is at the end near the door. The trolley often gets jammed at the opener unit end which would be with the door OPEN. So it is when you try to CLOSE the door that the unit will hum and not work.

FWIW, and to other posters these details must be clear in order for us to assist you in diagnosing a problem that we can't see.

Don is the one of the best at garage openers, follow his instructions and let us know how you make out.

Don, Sdello,

Thanks. It worked. I loosened the bolt. Clicked the button and it worked. Then I adjusted the "up limit". And yes I put the bolt back :-)

While we are on this subject. What can I do, if anything to make this thing run silent or at least less noisier than now?

Thanks once again.

Some suggestions:
make sure the door operates smoothly and is balanced correctly, independent of the opener. All the bolts on the door hardware should be tight. Lubricate the rollers. (with a failry lightweight oil like motor oil don't use grease)

make sure the chain is fairly taut and not flapping during operation.

If the unit is bolted to floor joists for a room above the garage, you might consider some rubber grommets or other vibration isolation.

Don and Sdello......

Hey guys, thanks so much for the repair. I, too, have a craftsman opener, but mine is a 1995 model 1/3 HP. Yesterday the temperature here fell from the 60's to the 20's and my opener just hummed when I hit the button. (FYI: the indicator light on the unit itself was blinking 5 blinks over and over.) I found your "fix" and tried the repair this morning. IT WORKED!!!! You guys ROCK!

Thanks again!
Jackie

I have a model# 139.53674SRT1. The sprocket that turns the chain above the motor housing is not turning at all. The motor is on or I hear a sound. The sensors are lined up properly. Any idas?

I am having a similary problem. I just install the craftsman 1/2hp 315mhz opener and works fine but the motor hums all the time. Do you know what is wrong?

Hi all. I've moved into a home with a Craftsman 41A3625 Garage Door opener. I have a set of 4yr old twins I'd like to protect from harm and there is no 'sensor' on the garage door sides, nor does it seem to auto-stop/reverse when it receives some resistence. Does that particular model support these safety measures? Does anybody know how i might obtain and add the sensors and/or activate that feature?

geoffmitch:
the lack of sensors means that the unit is pretty dated. Even if it were possible, it wouldn't be prudent to add sensors as the unit is pretty old. Best bet is to replace it with a new one (they all have sensors now).

FWIW: I suspect that the door has a reversing feature but the downforce is set pretty high so the corresponding reversing force is also high. Put a 2x4 on end at the bottom and close the dooor. See if it returns.

hope this helps.

"Posted by don_ (My Page) on Mon, Nov 6, 06 at 13:35

Remove that bolt and the door should then close. On the side of the motor unit you will find a control labeled 'up limit'. Turn this about 3 times in the opposite direction of the arrow printed on the cover and it should take care of your problem. Be sure to replace that bolt. "

Thanks Don- you just saved me much time, $$$, and aggervation... I was just getting ready to go to bed, and noticed that my garage door didn't shut when I hit the remote button. I had the same "buzzing" as others described. Sure enough, the track was tight against the bolt, so once the bolt was removed, the door closed just as you predicted. Only lesson learned here- my 2 up and down dial adjustments were numeric (Kg) I believe. Three rotations weren't possible (the dial only had ~270 degrees of adjustment). I turned it down a little bit, then the door wouldn't go up more than 8 inches. After a few atempts, I lifted the door while the motor was trying, got back in, turned the adjustment back to where it was, and I appear to be in good shape now. Thanks again!!! Repaired in 10 minutes without spending a dime :)

Don, You are the man. If I knew where you lived that tip would definitely be worth a case of beer! Thanks.

The cover for my motor is gone, so I don't know which direction to turn the control.

If we are still talking about the up limit control you turn it counterclockwise.

I have a Craftsman (date:) 6/97 (model:) 139.53677SRT1. There was no owner's manual for that model no. so I downloaded one close to it. The problem is that when I try to open or close the door, whether from the house control unit or the remote, all that happens is that the motor hums. Prior problem: Starting about 2 months ago, the door would get down to about 2 ft from the ground and stop. I could make it act right if I violently shook the door when it stopped. Prior to that, whenever the door would go down, it would make ungodly screeching noises, I assume in the rollers, which I have now oiled. After several sessions of my shaking the door to get it to close, the screeching stopped and all was well. But now I have the no-open, no-close humming problem. I've checked the trolley to see if it hits the bolt, and it doesn't. It latches about 3" before the bolt. I've oiled the rollers and tested the balance. I still only get humming. The control isn't on lockout. It seems to me that humming means the sprocket isn't turning, which makes me worry that I'm going to have to get a whole new g*d* motor. Also I can't figure out how to get to the sprocket. I can see that the chain is a little loose when the door is closed (and open), so I guess I'll try to tighten that a little. Otherwise, what could be causing this?

Remove the cover from the motor unit and check the drive gear. It is a white nylon gear just in front of the motor and it will be obvious if it is bad. The part number is 41A2817 and is available at any good door service company. It should come with instructions.

I have a Craftsman (date:) 6/97 (model:) 139.53677SRT1. There was no owner's manual for that model no. so I downloaded one close to it. The problem is that when I try to open or close the door, whether from the house control unit or the remote, all that happens is that the motor hums. Prior problem: Starting about 2 months ago, the door would get down to about 2 ft from the ground and stop. I could make it act right if I violently shook the door when it stopped. Prior to that, whenever the door would go down, it would make ungodly screeching noises, I assume in the rollers, which I have now oiled. After several sessions of my shaking the door to get it to close, the screeching stopped and all was well. But now I have the no-open, no-close humming problem. I've checked the trolley to see if it hits the bolt, and it doesn't. It latches about 3" before the bolt. I've oiled the rollers and tested the balance. I still only get humming. The control isn't on lockout. It seems to me that humming means the sprocket isn't turning, which makes me worry that I'm going to have to get a whole new g*d* motor. Also I can't figure out how to get to the sprocket. I can see that the chain is a little loose when the door is closed (and open), so I guess I'll try to tighten that a little. Otherwise, what could be causing this?

I have the same problem as ruby2, I think. I was looking for an answer but haven't seen one. Anyone with an idea?

disconnect the door from the opener and manually open and close the door. It should be easy to do with smooth operation and no binding, rattling, etc. the tension springs should allow the to stay 1/2 open and not drop or recoil in the up position.

If the above is true then the problem is with the opener and not the door.

Operate the opener with no door connected. The trolley should go towards the door for the closing cycle and away from the door for the open cycle. There should not be any unusual screeching noises or erratic action. If you just get a humming noise and there are no signs of the trolley being blocked, then the mechanism is jamming inside the unit.

If this is the case your options are:

1) open the case and see if you can find where it's jamming

2) call a garage door specialist to come and take a look at the opener for you

3) buy and install a new gdo

I would not recommend violently shaking the door as a method to fix the situation.