Microphone Wiring Diagram - CB World Make sure your CB mic is plugged in securely. Check for breaks or damage to the plug and cord. Check the pins in the radio for damage as well. Be sure you are pressing the CB microphone button all the way in. If it is a power mic or echo mic, make sure there is a battery in it! Visit our Troubleshooting Radios Article for other helpful information. Vintage HAM Radio / CB Radio Schematics - Service Manuals CB Radio Schematics / Service Manuals. Do you need a HAM / CB / Scanner-Monitor radio schematics / service information to repair, modify, test or install you vintage CB radio / citizens band transceiver? We carry a good selection of schematics / service manuals for vintage CB radios.