Repairing vintage microphones is a specialized industry, requiring knowledge of electronics and electricity, and the ability to work with delicate parts. Many individuals choose to repair vintage microphones for their "classic" sound, aesthetic purposes or as an investment. Many of the original microphone manufacturers of the early to mid-20th century have long since gone out of business, but the interest in vintage mics has prompted some manufacturers and individuals to offer aftermarket parts. Most microphones can be repaired with simple hand tools, but the more complicated and delicate units--such as tube and ribbon microphones--are best handled by professionals.

Instructions
Repairing the Cable

1 Disconnect the cable (if present and disconnectible) and test each of the contacts on both ends for electrical continuity with an electronic multimeter. If a wire within the cable has no continuity, proceed to the next step to check the connector. If all wires have continuity, the cable requires no repair. Skip this section and go to Section 2.

2 Disassemble the connectors on both ends of the cable. They may twist apart or require the use of a small screwdriver to loosen any set-screws that are present.

3 Inspect the inside of the connectors for loose wires and solder joints. Re-solder any loose wires and refresh solder joints by applying heat from the soldering iron followed by an application of solder. If the soldered area is visibly corroded or the solder will not stick, clean the area with dry emery cloth and try again.

4 Retest all wires and connector contact points with the multimeter. If all test areas show continuity, the cable is ready for use. If continuity problems are still present, or the cable or connectors show visible signs irreparable wear or damage, replace them with new cables or connectors.

Repairing the Microphone

5 Inspect the microphone and note any markings, model or serial numbers on the outside.

6 Carefully open the microphone body by unscrewing any set-screws or removable parts. You may wish to draw a diagram of the microphone and all parts removed for later reference. Alternatively, label each part and wire with masking tape and a pen for easier assembly.

7 Inspect the internal wiring for loose or disconnected solder joints, and re-solder if necessary. You may also replace severely corroded wires with new ones from your supply. Be certain you use replacement wire of a similar gauge thickness, wire type and insulation color if possible.

8 If the interior looks fine and all loose wires have been re-soldered or replaced, reassemble the microphone and test for operation by plugging it into an amplifier. If no sound is produced, proceed to the next steps.

9 Disassemble the microphone again and note any markings on the microphone cartridge and transformer. Contact a vintage microphone parts supplier to purchase replacements for these items.

10 Install the replacement cartridge and transformer when they arrive by soldering them in place with the soldering iron. Your notes from before will tell you exactly where the wires attach.

11 Reassemble the microphone and plug into the amplifier to test for operation.

Tips & Warnings
Read as much material as you can on microphone function, manufacture and repair before diving in to unknown electronics territory.

Shop around for the best price on replacement parts, but only purchase from reputable dealers and individuals.

If your vintage microphone manufacturer is one the the few still in business--Shure, Electro-Voice, Neumann to name a few--their parts and service departments may provide you with parts and advice. These companies are also known to offer excellent factory repair services if you find yourself over your head.

Tube microphones may contain dangerous internal voltage, even when unplugged for a period of time. Employ the help of a professional to repair tube mics and others that contain advanced electronics such as pre-amps, power supplies and capacitors.

Use caution when working with soldering irons and always wear eye protection. Irons can cause severe skin burns and molten solder can spatter without warning.