Elecraft KNB2 Manual - Manual (Page 5)

5
Trim and solder the leads of L1. When soldering, make sure that the solder binds well to the leads. If
the lead appears to be an “island” in a small pool of solder, chances are it is not making good contact. It’s a
good idea to measure from pad to pad using an ohmmeter to be sure the leads are making contact.
Wind and install L2 in exactly the same way as L1.
Inductor L3 is wound using 10" (25 cm) of enamel wire on an FT37-43 core (gray). Wind 15 turns
on the core, and prepare the leads as you did with L1 and L2. Install and solder L3 vertically as indicated
by its PC board outline.
Install 8-pin male connector P1 on the bottom of the PC board in the position indicated by its
component outline. Do not solder yet. The drawing below shows how P1 should appear viewed from the
left end of the board, with the component side up.
P1 (on bottom)
Components on top
Solder just one pin of P1, near the middle of the connector. Verify that P1 is now perpendicular to the
PC board and is seated completely flat. If not, re-heat the soldered pin and press down on all of P1's pins
until the connector drops into place. Once the connector is seated correctly, solder the remaining pins.
Installation
Turn the K2 off and disconnect any power supply or battery connected to the DC power jack (J3).
Remove the top and bottom covers. (Do not remove the heat sink panel.)
Remove jumper W5 on the RF board (near the heat-sinked I.F. amplifier transistor, Q22). It is best to
de-solder W5 and remove it completely rather than just cut it at both ends. If the noise blanker must be
removed later, W5 can be re-installed, or you can insert a wire between pins 1 and 6 of J12.
Remove resistors R88, R89, and R90 from the RF board (near J12). Be careful not to damage any pads
or traces when you remove these components.
Install a short jumper wire at R89. You can use a discarded component lead.
Install a 2.7 k resistor at R88 (this resistor is listed as RF-R88 in the noise blanker parts list).