use the DDS and LPF boards plugged into the sockets, then solder the pins, to ensure correct
alignment.
6) Fit and solder R1, the preset potentiometer
that sets the LCD contrast.
It is a slightly tight fit but apply pressure
carefully and evenly, and the pins of the
potentiometer will fit into the PCB perfectly.
Adjust this potentiometer to the fully clockwise
position initially.
7) Solder wire jumpers as shown in the
diagram below (red wires circled in
yellow), depending on your requirements.
These can be made from offcuts from the
other components e.g. capacitor leads. When
installing these wire jumpers, I find it
convenient to install them as a small semi-
circular arch, perhaps 5mm high off the board,
as pictured. This is so that later, if they need
to be removed (for different hardware options configuration), a convenient alternative is to just cut
them using wire cutters.
PCB Rev 3/4: please follow diagram below, not photo!
The W0-W1 and W2-W3 jumpers hard-wire the LPF into the circuit. Note that when a relay is fitted
at RL0, you do NOT connect these two jumper wires. The relay is part of another kit, the relay-
switched LPF board, that expands the capability of the U3 kit to sequence through up to 6 different
bands.
If R2 is installed, in order to reduce LCD brightness, then connect A1-A2 instead of A0-A1 (see
“hardware options” section below).
You may also install a jumper at the +PA and +5V connections at the bottom of the picture below, in
order to power the power amplifier (PA) with the 5V supply. You should leave out this jumper if you
intend to run the PA at a higher voltage. See more details in the “Hardware options” section below.
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