The following installation requires the removal of 1 resistor and the connection of 7 wires to the main circuit board of the radio. See the chart for the resistor, AM modulator transistor, AM Power, and AMC controls for your particular radio application. Mount the MD-1 toward the rear of the radio near the Modulator Regulator transistor on a flat surface of the PC board using the mounting tape supplied. Mount it on the topside of the board on surface mount radios and the bottom or solder side of the through hole radios. 1.Remove the resistor located near the AM Power control listed for your radio below. 2.Connect the RED wire to 13.8 volts at the audio amp IC or after the On/Off switch. 3.Connect the BLACK wire to ground. 4.Connect the ORANGE wire to the hole of the resistor removed that connects to the power control trimmer potentiometer. (On the Super Star 121 it will be the pad furthest from IC4}5.Connect the YELLOW wire to the other hole of the removed resistor. 6.Connect the WHITE wire to the center pin of the AM Mod/Regulator. 7.For a switch-able modulator, connect the GRAY wires to a SPST switch. In the closed position the modulator is off. If a switch is not desired, leave the GRAY wires disconnected and insulate them with shrink tubing. 8.For the higher power radios such as the RCI 2970DX, Galaxy 93T, and other radios a 15K resistor may be required across the gray wires of the MD-1. These radios may require 10-Watts minimum dead carrier for the modulator to work properly 9.Set the power and modulation to your desired settings. Higher modulation creates more swing.