 You can use the fine tuner echo to check if your processor microphones are working. Place the coil on the back or front of the fine tuner echo. Speak into the audio processor microphones. The green light on the fine tuner echo should flicker to the rhythm of your voice. If it doesn't, check that the microphones aren't muted and try again. If the green light still doesn't flicker, replace the coil cable and battery and try again. If your audio processor is still not working correctly, contact your CI Center for assistance.