DDS VFO Construction Manual – Issue 1
Page 9
Step 4: IC socket
The IC socket is installed next with the notch facing the right side of the PCB.
Step 5: Crystal oscillator module
Ensure pin 1 of the oscillator module faces the bottom left of the PCB.
Step 6: 5 volt regulator
The regulator lays flat against the PCB so needs the leads bent at right angle to fit through the
holes in the PCB. Insert into the PCB holes and secure with a 3mm screw and nut before
soldering the leads.
Step 7: Connectors
The Output connector is a 2 pin right angle header while the Power connector is a 4 pin right
angle header. Push them into the PCB so they lay flat against the board and then solder.
The ISP header is an un-shrouded 3 pin x 2 row header and the shorter pins are inserted into
the PCB and soldered.
The LCD connector is a 16 way male pin header and is mounted on the reverse side with the
short ends of the pins located in the PCB. Ensure it is pushed in completely and solder the end
pins first and check it is at right angle to the PCB before soldering the remaining pins.
Step 8: Rotary encoder
The rotary encoder is mounted on the reverse side. Insert into the holes and check that it is at
right angle to the board before soldering. It is not necessary to completely fill the mechanical
mounting holes in the PCB with solder.
Step 8: Microcontroller
Remove the microcontroller from the bag and insert into the IC socket ensuring pin 1 points to
the top right of the PCB towards the contrast control. It may be necessary to squeeze the rows of
pins slightly together to get it to fit into the socket.
Step 8: LCD
Solder a 16 way female pin header to the rear side of the LCD PCB.
The LCD can then be mounted onto the DDS VFO and mate with the 16 way male pin header.
Place four 12mm long nylon spacers between the LCD and DDS VFO PCB at each corner and
secure the assembly with 2.5mm screws and nuts.
