The Shure SM58 is noted for its rugged durability, but things can go wrong on occasion. Fortunately, the most common problems are easily remedied with basic soldering skills, and replacement parts are readily available from the manufacturer and many authorised Shure retailers. The SM58 is a dynamic microphone containing three internal parts: the cartridge, transformer and the 3-pin connector. Transformers rarely fail, but the cartridge is delicate and subject to damage from repeated or hard blows or falls. The connector wires are subject to pulling and twisting each time the microphone cable is inserted or taken off, and it is the most common problem.
Remove the connector from the bottom of the microphone by inserting a small screwdriver onto the recessed setscrew and turning clockwise.
Insert a pair of needle-nose pliers onto one of the connector posts and gently pull the connector straight out of the microphone bottom.
Visibly inspect and tug lightly on the three wires to check for a solid connection. The black wire is attached to pin 1, blue to pin 2 and red to pin 3. If any of the wires are loose, solder them back onto the proper pin using a soldering iron and rosin core solder.
Gently push the connector back into the microphone until the set screw is visible through the hole on the bottom side of the microphone. Turn the setscrew counter-clockwise with the screwdriver to lock the connector in place.
Plug the microphone in and test for operation if a connector wire repair was made. If the connector wires were intact, proceed to the next step.
Unscrew the metal windscreen from the top of the microphone by turning it counter-clockwise. The microphone cartridge (also called a "capsule") will now be exposed.
Grasp the cartridge with your thumb and forefinger and gently lift it out of the microphone.
Inspect the green and yellow wires and tug lightly at each to check for a solid connection. If a wire is loose, solder it back on with a soldering iron and solder.
Press the cartridge back into the microphone and replace the windscreen by screwing it on clockwise.
Plug the microphone in and test for operation if a cartridge wire repair was made.
If all wires are intact, take the microphone to an authorised Shure service centre for evaluation.
Shure replacement cartridges can be purchased and installed by the user by soldering two wires. It is recommended that the mic be checked out by a professional to determine cartridge failure before purchasing this expensive part. Regularly check the connector setscrew for tightness to avoid future problems. This is one of the most common Shure SM58 maintenance procedures.
Don't attempt to dismantle the cartridge for further troubleshooting. This is an advanced repair and requires special equipment and knowledge. If repair is attempted, your warranty may be void. The transformer is mounted in the centre of the SM58 with epoxy. Attempts to remove it may cause damage to the transformer and wires.