Buzzing. I have a neumann Tlm 193 which one day during a recording session suddenly started

Question

I have a neumann Tlm 193 which one day during a recording session suddenly started buzzing as if a wire was grounding or perhaps touching something. I have not used it since but I would like to. I do not know about wiring inside microphone or where to start with fixing and/or assessing problem.Think you might know?