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

Page: 6 / 47

revised 3 Feb 2021 Bayou Jumper revB Assembly Manual page 5 of 46
Enclosure
It would be best to prepare the enclosure before beginning assembly of the PC boards, in
case any minor sanding or filing were to be needed to refine the fit of the boards into the box.
The enclosure must be prepared to
mount the circuit boards. Included in
the kit are four
3/8” wooden blocks that
must be glued into the four inside
corners of the box. Use wood glue to
attach them
(Elmer’s Carpenter’s Wood
Glue
– the yellow kind). They should
be spaced down from the rim of the box by the thickness of two PC boards
(about 1/8”) – use the two crystal adapter boards as a thickness gauge.
After the glue has dried for several hours, place the top panel circuit board onto
the four corner blocks. Use a pencil to mark through the four corner holes in the
top panel board onto the corner blocks. Remove the top panel.
There are four wood screws in the parts kit for mounting the circuit board
assembly. If driven directly into the corner blocks, there is a risk the blocks will
split, so it is necessary to drill pilot h
oles for the mounting screws. Use a 1/8” bit
in a hand drill (or drill press if available)
, drill down approximately 1/2”.
Solder Filling Selected Vias
Vias are small plated-through holes that electrically join the top and
bottom copper layers of the circuit board. If you look closely at the heavy
traces near D1 and C22 you’ll see two groups of four vias in the middle of
those traces. These traces, and vias, carry the full transmitter current
– a
substantial fraction of an ampere. To ensure a low resistance path these
eight vias should be
filled , that is, enough solder should be flowed into
them that the solder is level with the via pads on both the top and bottom
sides. The same should be done to the vias at the center of each of the
etched inductors.
□
Fill the four vias in the heavy trace near D1
□
Fill the four vias in the heavy trace near C22
□
Fill the three vias in the centers of the three etched inductors L3, L5, and L6