G.D.Opener worm stop turning after sprocket replacement.
On a sears garage door opener I changed the main sprocket and when I turned the opener on without the chain the worm and sprocket turned fine. When I put the chain on (without the door hooked up) it ran rough like the chain was too tight and it traveled only a few feet on the track. I hit the button again to see if it would run smoother, it only moved a little and then stopped. I hit the button again and all I heard was a short buzz/hum and then a click. I took off the chain and hit the button to see if that would help and nothing. The worm does not turn. I took the sprocket out and tried it again and nothing. Did I burn out the motor? Did it come disengaged somehow? Should I just buy a new one? Please help if you can.