Sennheiser MD421 Microphone

This classic Sennheiser MD421 Microphone came in DOA and deserved to live again. Some of these older mics have a bucking coil to reduce RF interference in series with the coil on the diaphragm – this one had an open circuit fault in the bucking coil and had to be unwound to the break and re-wound to complete the circuit. There are some very fiddly parts in the filter assembly in these mics so they are a very slow and steady type of repair job.