MFT-20 DSB Transceiver Kit
Page 14
Pin "headers"
To build the complete transceiver you must place pins in: MIC(3), 12-14V(2), ANT(2), SPEAK(2), EXT-
VFO(2), J1(2)
Place “jumper” between pins “J1”.
Note: If you want to build only the RX section, then place these pins: +V(1), +VRX(2), SPEAK(2), and
RX-ANT(2).
Turn the board over and insert and hold the header in place, using a “jumper” placed on the header while
you solder the pins to avoid burning your fingers. Use your other hand to hold the soldering iron and
move the board towards the solder to solder the headers in place. If you have someone available to help
you, it will be much easier!
Transistors
All of the transistors have their type printed on the component body. Place them according to the
corresponding component outline printed on the circuit board.
Transistors Q1and Q2 of the type BC547.
Q3 is a PN2222
Q4 is a BD135; the face with printed letters should be facing the top of the PCB (L7, L9 etc.)
Q5 is the output TX transistor. See picture showing the position of Q5.
The case of Q5 should be electrically isolated from the heatsink. Use the plastic washer and the mica
sheet provided with the transistor. Fasten it with the 10mm screw, nut and M3 washer. After mounting
the transistor to the heatsink, verify with a multimeter that the transistor case does not make contact with
the screw or with the heatsink. It is also recommended to apply a dab of thermal grease on both sides of
the mica sheet. Note that the screw goes through the heatsink's upper hole.
