Hi, i have a model #53975 1/2 hp Craftsman garage door opener that broke the washer or bushing under the sprocket. So i ordered a sprocket assembly that came with worm gear. I installed everything with not too much swearing. Now when i press the button the opener goes 6 inches up then immediately 6 inches down and stops. I know other people have been having this same problem, and i moved the collar all the way against and the interruptor cap is on. But it's still not working, 6 inches up then down.

My question is can i buy a different model 1/2 hp opener and just swap it?