Check the RX lights on the mic. If they don’t light up when the unit is turned on, you simply have a dead battery. Switch the battery out for a fresh one if this is the case.
Check the element. If the RX light is on but no sound is coming out, you may have a defective or shorted element cord. Look for tears in the rubber coating surrounding the element wire or very angular bends around the connection to the transmitter. These are all usually signs of element damage. If this is the case, replace the element.
Wiggle the connection between the transmitter pack and the element. If you are getting a popping sound or static in your signal, there may be a loose or shorted wire in the connection. Wiggling the connection usually will allow the two to make better contact, cleaning up the signal.
Look for a clean channel. A static-filled signal also can indicate radio interference on the transmission frequency. By moving the transmitter and receiver to a clean channel you won’t have the two signals colliding and creating distortion.
Adjust the gain on the transmitter unit. While the receiver may control the signal output, the transmitter controls the input. If this is set too high, the signal will peak before it reaches the receiver, creating a lot of distortion. Simply pull down the gain control on the transmitter to clean up the signal.