James wrote:
This is a Craftsman unit, about 12 years old. It uses the chain, but
has worked fine.

Today, the door would not go up and down. The unit buzzes (loud)
like the motor is trying to run, but the chain does not move. Can
unhook the door from the chain, and run it up and down manually, but
the drive motor seems to be buzzing and not functioning properly.

Is the a home repair, or more likely a worn out unit needing
replacing ?

Thanks

James

This model may have nylon gears - and they often get stripped. A new set of
gears is cheap and easy for the homeowner to replace.