Have an old Rockwell table saw model 34-466 with a Rockwell 83-621 motor. Was working fine. Then when I turned it on, the blade rotated about 1/2 revolution very slowly and stopped. When I turn the saw off, I can see the switch move to the off position. When I turn it on, I can see the switch move on and hear it click. The motor doesn't run or the blade turn and I am getting a faint humming sound when in the on position. I can turn the blade manually just fine, so it hasn't frozen. Any ideas on what might be the problem? Thanks to all for your help.