Originally Posted by piper
I have an MXL 990 that hums. I have checked that there is continuity from pin 2 to the body, and there is, but I have no idea what to do next. What parts are most likely to cause hum?
Pin 2 should not have continuity with the body. If pin 2 is grounded that may be the issue. Trace the wires and check the voltages on pin wire 2 and 3 (at the circuit board) they should read around 48vdc. Pin 1 is ground = 0vdc
Make sure the body is screwed on tight. You can also sand the edge of the body to get a better connection.