I have a very nice older drill press. Some were in its life time it was converted to DC. It has reverse so I was using it to tap some holes. It just stopped working. The controller is home built and unfortunately I have yet to wrap my brain around electronics. I understand enough identify the 4 diodes set up as a rectifier bridge to convert AC to DC. Other than that it is all gibberish to me. I did test the motor and there is voltage at the brushes when it is turned on. The brushes look OK to me. If any one could help I would really appreciate it. I do have a multimeter and I have a simple knowledge of using it. Thank you