4SQRP Bayou Jumper 40 Meter CW Transceiver, Assembly & Instruction Manual

Page: 7 / 47

revised 3 Feb 2021 Bayou Jumper revB Assembly Manual page 6 of 46
Preliminary Assembly
The large components (four potentiometers, BNC jack, and rotary switch) will be installed
first. In order to ensure that these components properly line up with the holes in the front
panel, test fittings will be performed
.
□
Locate the six 5/8” hex standoffs and twelve of the 6-32 x 3/8” machine
screws. Use six of the screws to install standoffs on the bottom side of the
Front Panel PCB at the six perimeter mounting holes ( NOT the four corner
holes).
The first components to be installed on the Main PC board will be the four
potentiometers. R6, R8 and R10
are 50 k pots, marked “503” while R1 is a 5 k
pot, marked “502.” All four of these potentiometers will be installed “standing
proud” to ensure that there is enough shaft above the panel to accept the knobs
securely.
□
Place the main PC board flat, right side up, on a hard
work surface, and insert the mounting tabs and pins of R8
(50 k,
marked “503”) through the PCB mounting holes so
that the tips of the two tabs rest flush against the work
surface without extending past the bottom of the board. This
ensures that the shaft of the pot sits as high as possible.
Notice that when the two mounting tabs are flush with the bottom of
the board, the three contact pins will not quite penetrate all the way to
the bottom. This is normal and correct. The holes are through-plated,
and when soldered the connections will be solid.
□
Make sure the pot shaft is vertical, and then solder only
one of the mounting tabs to the board. It will be easiest to
solder on the top side of the board.
□
Place the front panel with its standoffs in position atop
the main PCB. Use three screws to temporarily secure the panel to the main
board. Inspect the alignment of R8 and make sure that the shaft can turn easily
without rubbing the sides of the hole. If needed, reheat the soldered tab and
reposition the part.