I have a microphone out, is there anything I can check to determine if a service technician needs to visit?

The microphones, like the cameras, have two connections. One is at the microphone and the other is on the back of the DVR. Both connections are twist ons and should be very tight and secure. If they are lightly making a connection the microphone will make a clicking noise when it is enabled due to the connection dropping. If everything seems secure and microphone still doesn't sound right it may be time for a technician to inspect it further.