Adding The Workman MD-4 To Magnum 357DX

Adding the MD-4 to the Magnum 357DX is simple if you don't want the LCD meter to read any signal. The MD-4 external meter measures current and draws the voltage down to the LCD meter, thus the LCD won't read once the MD-4 meter is connected to the same signal feeding the internal meter. Remember, the LCD meter only has a real resolution of five segments. Once the MD-4 is hooked up, the internal meter won't be looked at again. If it's desirable to have both work, go to the article titled Adding The Workman MD-4 To Other Radios. You can add a 2.5mm jack Mouser Part # 161-1650 to the back of the radio to accept the MD-4 plug. Run a wire from the tip connection of the jack to the wiper of RV1 or RV8. It doesn't matter which potentiometer you connect to, they are tied together. The contact point is the single lead opposite the two on the other end of the potentiometer. Connect a wire from ground to the ring terminal of the 2.5mm jack. Once installed, turn the MD-4 adjustment fully clockwise and then calibrate the "S" meter as usual. To calibrate the RF meter, put the radio in FM and on a dummy load adjust the meter to the last line at the far right of the scale. The meter leads connect to a 13.8 Volt source either internal to the radio, an external power source, or a vehicle dimmer control. Bob F

January 2002 Web Edition