Remove the microphone's front grill set screws using the jeweler's screwdrivers. Pull the grill away from the microphone body, revealing the crystal element.
Slip a jeweler's screwdriver in between the element's rubber gasket and the microphone body, breaking the seal. Pull the element and gasket away from the microphone body carefully.
Remove the gasket from the element by rolling it away from the element's edge.
Shake the crystal element carefully next to your ear. If a rattling sound is heard, the element must be replaced.
Check the solder connections on the rear of the element. A good solder joint should look uniform and silvery gray, with no cracks or looseness. Re-connect these wires if required with the low wattage soldering iron and electrical solder.
Check the internal wires on the microphone. Many vintage types of wire can become brittle and break over time due to their construction. If any corrosion or physical breaks are detected, replace the wires with the soldering iron, solder, wire strippers, wire clippers and hookup wire.
Reassemble the element, gasket and front grill using the jeweler's screwdrivers.
Remove the audio connector from the microphone with the jeweler's screwdrivers, revealing the internal element wiring. Place the multimeter's leads on the audio connector's pins to test for shorts. If a short is detected, inspect the connector for physical breaks or excess solder buildup. Unsolder any buildup with the soldering iron and solder wick. Replace the microphone's audio connector if physically damaged.
Remove the push to talk switch (if equipped) from the microphone housing and inspect the solder joints for cracks or breaks. Solder any bad connections.
Place the multimeter's leads on the switch's solder connection to test. The meter should read a significant change in electrical resistance when the switch is engaged and disengaged. If the meter reads no change, replace the switch by unsoldering the switch's wires using the soldering iron and solder wick, freeing the switch from the microphone. Solder these wires to the same terminals on a replacement switch. Install the new switch assembly into the microphone housing.