Elecraft KX1 Manual - Manual (Page 55)

54
E
LECRAFT
Temporarily secure Q6 to the standoff with a 4-40 flat head
screw. Tighten the screw enough to hold Q6 securely and parallel to
the circuit board.
Use your long-nose pliers to adjust the leads so the flat side of the
transistor is parallel to the circuit board. The flat side must face
AWAY from the board. It will rest against the thermal pad you
installed in the top cover and must make good contact to transfer heat
efficiently.
Solder the three leads to Q6. Trim them flush on the bottom side
of the board.
Remove the flat head screw holding Q6. If a 2SC2166 is
installed, the soldered leads should hold the shoulder washer in place.
Conduct a thorough visual inspection of the board. Use a
magnifier. Check especially for the following:
_ Diode D4 is oriented correctly as shown in the Parts
Placement diagram in Appendix F.
_ All joints soldered with no shorts between solder pads.
_ All components installed. On the bottom are some labeled
pads that will have no wires in them. They are connection
points for the optional KXB30 30 meter or KXB3080 80
meter band module. These pads are labeled “A”, “B”, “C”,
“D”, “5” and three pads labeled “G”.
i
If you installed a 2SC2166 (metal tab) transistor at Q6,
NEVER install a metal screw in the tab of Q6 when the unit is out
of its case for testing. The metal tab of Q6 is connected to the +
side of the power supply and the screw will short the supply to
ground when power is applied. This may cause serious damage to
the circuit board or other components.
Connect your DMM ground lead to one of the metal stand-offs
mounted on the board and make the following resistance checks:
_ Q4 Emitter (terminal farthest from edge of board) 20
to 24 ohms
_ Q4 Base (center terminal) > 10k
_ Q4 Collector (nearest edge of board) > 10k
_ Q5 Emitter (terminal farthest from edge of board) 50
to 70 ohms
_ Q5 Base (center terminal) > 10k
_ Q6 collector (metal tab if 2SC2166): > 500 ohms
Place the three button caps on the pushbutton switches. Press
down on each cap to snap it in place.
Fit the board into the top cover as follows:
_ The control shafts will fit through the holes.
_ If the pushbutton switches don’t line up properly with the
holes in the cover, use a long tool to reach between the cover
and the circuit board to nudge the caps into the holes.
_ Finally, you will need to push down gently on the key jack to
make it snap into its hole in the cover.
_ Check the standoffs at both ends and confirm that they are
resting against the cover.
Secure the board to the cover with three 4-40 x 1/4” flat-head
screws. Do not over-tighten any of these screws.