Elecraft KXB3080 - Manual (Page 15)

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Thread leads 2, 3 and 4 of each core through their respective solder pads on the LPF1 PCB (see Figure
11). Lead 1 to each toroid will be connected directly to the KX1 PCB later. Position the toroids against the
LPF1 PCB and directly over the circles drawn on the PCB as shown in Figure 8. Be sure the toroids are
centered and do not extend farther over one edge than the other. On the relay side of the PCB, be sure
clean, tinned lead is visible in each solder pad, then solder and trim all six leads.
Identify the negative lead of electrolytic capacitor C9, 10 µF, 35V (10). The negative lead is the
shorter lead and there will be a stripe with a minus (-) sign on the capacitor next to that lead. Position the
capacitor against the LPF1 PCB alongside the relay next to the ground wire exactly as shown in Figure 12.
Solder the negative lead to the ground wire on the LPF1 PCB as shown.
Cut to length the green hook up wire insulation you saved and slip it over the positive lead from C9
as shown in Figure 12. Route the positive lead of C9 over the top of K2 to the pad shown in Figure 12, so it
rests against the relay. Do not solder yet.
Pass Capacitor + lead
through the - pad. Do
not solder yet .
Insulation from green wire on
capacitor lead (see text). Wire
must rest against top of relay.
Capacitor - lead
soldered to bare
ground wire at
+ pad
Note that the + and - marks were printed on the PCB incorrectly
during fabrication. Connect the capacitor as shown.
Figure 12. Installing C9 on LPF1.
Remove L1 and L2 from the KX1 PCB. Clear all the solder from the pad holes and flush trim to the
KX1 PCB all the capacitor leads in the area near where L1 and L2 were removed.
Fit the LPF1 module in the space formerly occupied by L1 and L2. Place the L1-1, L2-1 and inductor
common leads through the solder pads on the KX1 PCB shown in Figure 13. The module must be
positioned against the KX1 PCB and J7 exactly as shown in Figure 8, with the windings on the toroids
flush with the edge of the KX1 PCB. Lead L2-1 fits between the LPF1 PCB and J7 to reach the solder pad
on the KX1 PCB directly behind the LPF1 PCB. If you have a KXAT1 antenna tuner, ensure it fits in place
as shown in Figure 14 before soldering the LPF1 leads. When you are satisfied with the fit, solder the
inductor common and ground leads to hold the LPF1 PCB in place. The ground lead is soldered to the lug
for potentiometer R1. It does not pass through the PCB. Carefully check the routing of green wire L2-1
and ensure it does not short against the solder pad for L2-4 at the corner of the LPF1 board or touch the L2-
4 wire.