The Shure SM58 microphone is built for strength and durability. However, microphones experience lots of wear and tear. Microphones need regular maintenance like any other electrical appliance. Dirt and debris can build up in the microphone and interfere with the electric signal or make the microphone produce strange noises. Routinely cleaning a microphone ensures the microphone's longevity. The most common problem with a microphone that doesn't work is a broken wire. This is usually a simple fix.
Cleaning the Microphone
Unscrew the grill from the microphone. Place the grille in a solution of mild detergent and water. Dirt, debris and bacteria build up on microphones that are heavily used. Cleaning the grill not only makes it more sanitary, it protects the wiring in the microphone as well.
Scrub the grill with a toothbrush, and allow it to air dry.
Scrub the foam diaphragm with a soft brush. Hold the microphone upside down to prevent moisture from getting into the microphone. Lightly dip a soft brush in the soap and water, and gently clean the foam diaphragm. Allow it to air dry.
Clean the XLR connector, the three-pronged adapter at the bottom of the Shure 58 that connects to the microphone cable. Over time, oxidation can build up on the metal connectors preventing them from making a secure connection to the microphone cable. Use a contact cleaning solution, such as Pro Gold GxL or Deoxit, to clean the connectors. Apply the contact cleaner to the XLR connector and gently clean it with a soft cloth.
Unscrew the parts of the Shure 58. There is an upper section and a lower section.
Look for broken or loose wires. Broken wires are the most common problem with microphones. The wires are easily visible in the upper section of the microphone. Remove the ring and plate in the lower section to access the wires.
Re-solder loose wires. If the wires are loose or broken they can be easily soldered back in place. Heat a soldering iron and reconnect the wires. If the wires are not loose or broken continue to the next step.
Unscrew the XLR connector. Remove the XLR connector from the base. Inspect the wires. There are four color-coded wires. If one of the wires is loose, solder it back in place. If two or more wires are loose, reconnecting the wires is more difficult. Find a wiring schematic for your Shure 58. Use the schematic to reconnect the wires to the appropriate spot.
Take the Shure 58 in for professional maintenance. The last culprit is broken wires inside the microphone capsule. Determining if a microphone capsule is bad and repairing a microphone capsule is a job for a professional. Working on the capsule yourself runs the risk of doing more damage to the microphone.