MFT-20 DSB Transceiver Kit
Page 11
ASSEMBLY
You can use the “individual parts list” or the “value/quantity parts list.” Using the “value/quantity parts list”
is the quickest way to mount components since all the circuit board components of the same value or
type can be placed one after the other. However, you will need the “individual parts list” to know how
each component is identified and its location on the circuit board. Depending on your personal
experience, you may prefer the individual parts list and feel more confident using it.
The 143-quadrant component layout map makes it very easy to find the location for all the components.
After mounting each component, it can be marked off in the “checked” column.
It is highly recommended that an inventory be taken of all the components to make sure that everything
is there and ready for assembly. Each constructor may have his/her own method of organizing the
components. One suggested method is to use a block of styrofoam packing material and poke the
components into it. The components can be sorted by type, value and size (ohms, micro-farads etc.).
RECOMMENDED ASSEMBLY SEQUENCE
Resistors.
The resistors are installed first. Mount all the resistors R1 to R35 and trimmers P3 – P4.
P1 is the Rx gain potentiometer and P2 is the TUNE potentiometer, which will not be installed yet.
Refer to the parts list, and select the first resistor, R1. Bend the leads as close to the component body as
possible, and place them into the appropriate holes according to the component outline printed on the
circuit board. Be careful to avoid confusing the resistors with the axial inductors which are a bit thicker.
All of the resistors have a light-colored body and a gold band on one of the ends. Inserting the resistor
leads into the holes, push down on the body of the component so that it rests flat on the board, hold it in
place, and then slightly bend the leads to hold the resistor in place. Then turn the board over and solder
the leads to the printed circuit trace. Make sure that the resistor body lies flat on the board so that its
leads are as short as possible. Please read the notes about soldering, as poor soldering is the most
common cause for a kit failing to work for the first time. After soldering them, cut the excess length off
the component leads as close to the joint as possible. Mount the next resistor in the parts list in the same
manner and continue until all the resistors are mounted.
The values which are in decade increments can be easily confused, such as 470, 4K7 and 47K, so be
sure to verify the colors before soldering the component in place! If you are in doubt, use a multimeter to
check the resistor value.
