If the unit hums when you turn it on, but it’s not jammed, the motor is probably bad. When you have a bad motor, it’s time to replace the whole disposer.
IT’S GRINDING OR DISPOSING POORLY
If the drain line is clear but the disposer still does not seem to grind up food very well, your disposer may be worn out. As disposers age, they gradually wear out and/or rust internally. Eventually, all disposers lose their ability to grind food effectively. If your disposer has reached this stage, replace it.