Sears Craftsman 1/2 HP Opener... cradle will not move, but motor is working

[AdamInKC]

I have an older Sears Craftsman 1/2 HP garage door opener. The FCC ID is HBW1D3605 and I cannot see all of the model #; however it starts with 41A3. This morning I went to open the garage and it went up around 6" and then the motor continued to make noise; however the cradle stopped moving. I know the track/springs are fine because the door easily lifts open after I disengaged it. What could this be? From reading other posts, it sounds like the nylon drive gear. If so, does anyone know the part # or do I need to verify the model # completely?

Also, are there instructions anywhere on how to replace this?

Thanks in advance!

[gdoorpro]

gear kit

This part has been exactly the same for a very long time. Go to any garage door service company, tell them you have a craftsman chain drive and you need the gear and sprocket kit. They will know what you need.

I posted instructions for this in a previous thread. If you can,t find it I will post a link here later.
Ryan

[AdamInKC]

I installed a new gear drive and worm gear last night and that issue is fixed; however now I have another issue. I was adjusting the up/down limit and force after I completed the installation and now the door moves about 6 inches and stops. I removed the chain from the sprocket, closed the door and removed the limit switch and manually adjusted it so the contact was touching for the closed position. I then reattached the chain and tried opening the door. The door opens 6" and stops. If I press it again it goes up a little more and stops.

I watched the limit switch while it was running and the motor is stopping without even being close to touching the contact for the open position.

Also, I have tried high, medium and low for the force setting and this did not help.

Any insight you might have would be appreciated!

[AdamInKC]

The tracks are fine... door goes up easily when disengaged.

I purchased an RPM sensor today because reading other forums other people had the same symptoms and this was the culprit.

[AdamInKC]

The RPM Sensor fixed this issue... all is good!