Microphone is covered with something. Cable is disconnectedcheck connector. If another microphone works in same input, themicrophone cable may be damaged. The knob on the microphone mixer is tumed down too low. Remote site volume is too weak or too loud.
Tape has record safety tab removed.
Make sure you pushed the correct button on the VCR Record Switcher that corresponds to the site you want to record. VCR Playback - no sound in remote site. Remote site does not have its BiAmp audio amplifier turned up high enough to receive sound from sending site. VCR - no picture on playback. Put tape into PLAY mode.