Today I went to tumble some brass for the first time in 2 years and the vibratory tumbler was running slow and feeble, what most people would call a "burned out" motor. Instead of dropping $200 on a new Dillon tumbler, I spent all of 10 minutes to take it apart, clean the motor rotor and stator, lube the bearings and reassemble. It now runs like it's brand new. Lots of nastiness gets into those tight clearances and it's worth it to clean every now and then.
I just fixed mine yesterday. The weight bar came loose. Had worn the lock bolt down so it couldn't be tightened anymore. Retapped it and put in a nicer locking point set screw. Running like a champ.