48 ELECRAFT
Locate all of the small glass-bodied diodes. You should have a
number of 1N4148 diodes, and one 1N5711, which will be similar in
size but should have different markings. Use a piece of masking
tape to identify the 1N5711 as "D9, 1N5711."
Install the following diodes, located near the outline for
toroidal transformer T5, in the synthesizer area. Be sure to orient
the diodes according to their outlines.
__ D11, 1N4148 __ D13, 1N4148
__ D6, 1N4007 __ D7, 1N4007
Varactor diodes have a small plastic package, like a TO-92
transistor, but with only two leads. Sort the varactor diodes into
groups: type MV209 and type 1SV149. (1SV149 diodes are labeled
"V149" and may have a center lead that has been cut flush with the
body of the device.) The K2 will not function correctly if the
varactor diode types are interchanged.
Install the MV209 diodes listed below. The flat side of each
diode must match the flat side of its PC board outline. These diodes
must be pushed all the way down on the board to prevent stray
signal coupling. Bend the leads slightly to hold them in place. D16
and D23-D26 are in the front-left corner. D39 is to the right of J7
(Control board).
__ D16 __ D23 __ D24
__ D25 __ D26 __ D39
Note: Do not install D19 and D20. These are supplied with the
planned K60XV option, which should not be installed until the K2
has been aligned and tested.
Install type 1SV149 diodes at D37 and D38, near the SSB
option connector. Keep them flat against the PC board, with no
excess lead length.
Install the remaining 1SV149 diodes listed below, keeping them
flat against the PC board, with no excess lead length. D17, D21 and
D22 are in the front-left corner. D29 through D34 are on the right
side near the crystal filter.
__ D17 __ D21 __ D22
__ D29 __ D30 __ D31
__ D32 __ D33 __ D34
Install the TO-92 package transistors listed below. Start with
Q17, near the middle-left edge.
__ Q17, 2N7000 __ Q16, PN2222A __ Q18, J310
__ Q19, J310 __ Q20, 2N7000 __ Q24, J310
__ Q25, PN2222A
Install Q21 (2N5109), which is located near U1 in the middle
of the board. Align the small tab on the transistor’s case with the
tab on its component outline. Bend the leads on the bottom to hold
Q21 in place, then solder.
Install Q22 (2N5109), which is to the right of the
"ELECRAFT" label. Make sure Q22 is flat against the board before
soldering.
Carefully press a 3/4" (19 mm) dia. by 0.25" (6.4 mm) high
star heat sink onto Q22. The heat sink should be pressed down as
far as it will go, and should not touch the components around the
transistor. The heat sink is fragile. If you need to spread it
slightly, use a blunted wooden pencil or a plastic wire nut.
Install Q12 (2N7000), which is to the right of Q22.
Install Q23 (2N7000), near the right-front edge of the board.
Install C167 (.001 µF, "102"), which is near J11, the connector
for the SSB adapter. The leads on this capacitor should be formed
to match its PC board outline.
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