I have a craftsman/chamberlain 1/2 horse garage door opener that came with the house. last month, it spit the chain, which i put back on and noticed that the shaft had a ton of play in it, and figured that i'd probably need to replace the opener soon. I tightened the chain up and hoped i could get a few more months out of it.
Earlier this week i accidentally left something in the door opening, which was the last straw. The sprocket sheared off of the end of the shaft. I thought "well crap, now i get to replace the opener." The info on the side says it was manufactured in 1993, so i figured its time had come. I had helped a friend install one in his new house a while back and knew it was a giant PITA and wasn't looking forward to it. I went to HD right before they closed and looked, but wasn't quite happy with the prices and options, so headed home to see what kind of deals are out there since i have amazon prime and could likely get something shipped to me for free.
Then i found that there are replacement parts for everything in the unit between the motor and chain. for $30 shipped, i had this at my door two days later: 
It comes with the motor drive gear, large shaft gear, new logic board drive gear, and new roll pins and bushings for everything.
total time was about 2 hours from start to having a functional opener again. biggest hassle was that the wire for the wall button couldn't be disconnected, so i had to hang the unit from zip ties in order to get at the top since its a flush mount.
supposedly this part works for all craftsman/chamberlain chain drive openers made since 84, nice to know that there are still things being made that are still made to be repaired rather than replaced.
