Dynamic coil microphones rely on the principle of magnetic inductance to translate sound pressure waves into electrical impulses. Located within the dynamic microphone's capsule is a diaphragm that moves a voice coil within a magnetic field. This voice coil consists of many turns of delicate magnetic wire. When this coil is damaged or shows no electrical resistance when tested, the dynamic microphone's voice coil must be rewound.
Unscrew the dynamic microphone's windscreen grill and pull it away, revealing the capsule.
Remove any protective plastic screens over the capsule's diaphragm by gently pulling them away.
Locate the two solder points connecting the voice coil wires to the microphone's output section, typically found on the side of the capsule.
Unsolder the voice coil from the output section wires using a low-wattage soldering iron and electrical solder. Set the soldering iron on a low heat setting to prevent damage to the capsule.
Remove the diaphragm from the capsule by gripping the sides of the diaphragm and very gently pulling away from the capsule.
Unwind the remaining voice coil wire from the diaphragm, removing it completely.
Wind the 30-gauge enamelled magnet wire 100 times around the diaphragm's voice coil section by hand. Use a back-and-forth motion to ensure even coverage and a flat coil. Leave 2 inches of extra magnet wire on both ends of the coil.
Replace the diaphragm into the capsule. Ensure that both of the new voice coil leads run to the solder connections for the microphone's output section.
Scrape away the enamel finish on both of the voice coil leads with the edge of a small hobby knife to allow solder to stick to the wire.
Solder the scraped voice coil leads to the microphone's output section.
Replace the capsule, protective screens and grill back to the microphone body.
Most dynamic microphones employ delicate diaphragms and voice coils, and you must take extreme care while removing and rewinding the capsule.
Be sure other possible microphone malfunctions have been ruled out before undertaking this very difficult task. Any handling of the diaphragm can cause damage to the mic or change its sound, and should only be undertaken as a last resort.