Our power antenna would make a noise like it wanted to go up or down... but wouldn't.
Pulled it out & opened up the cable spool area & found a little nylon wheel that had broken it's shaft & would not maintain contact with the toothed cable.
Fix was made possible by drilling from the reverse side to expose the back of the broken shaft & pushing the embedded broken piece out. Then reinserting a shaft that had been cut from an old drill bit of the 'same' size.
After cleaning all the old crud/grease out, lubing, & reassembly it is working quietly.
Probably could keep it working without breaking if the 'crud' was cleaned out every three years or so.
Total time about one hour. Cost nothing since old drill bit was broken anyway.