The Model R131 is a direct replacement cartridge for the Shure Model 527B microphone, and the Model R132 is a direct replacement cartridge for the Shure Model 527C microphone. To replace either of these cartridges, follow these steps:

1. Remove the three No. 6 Phillips head screws securing the case halves and carefully separate the case halves.
2. Using a low-wattage (50 W or less) soldering iron, unsolder the leads connected to the present cartridge.
3. Remove the retaining ring from the back of the cartridge, and carefully remove the support ring, cartridge, washer, and pad from the chassis module.
4. Place the pad and washer on the replacement cartridge and slide the replacement cartridge into the chassis module. Replace the support ring and the retaining ring.
5. Solder the leads to the replacement cartridge terminals. Refer to the Internal Connections Diagram for proper lead connections.
6. Insert the chassis module in the case front and the switch button in the case back. Fasten the case halves with the screws previously removed.