How Do You Remove A Food Disposal?

I accidentally had a bunch of soil go down my kitchen sink drain where the food disposal is. It has not worked since. We thought at first that there was just a small rock restricting movement of the grinders. I have completely cleaned out everything I can possibly see down the drain and it still will not work. I wondered if I blew the motor, but my husband, an ex-electrician, seems to think it is still just stuck. We can hear a hum when I flip the switch, but nothing moves. What do I do to check for that?