3
Ref.
Description
Qty.
J12 (RF board)
Conn., 8 pin female, 0.1" spcg., gold, Samtec SSW-108-01-G-S
1
HDWR
Split lock washer, #4 (
Note
: 2 spares provided)
6
HDWR
Machine screw, 4-40 x 1/4", phillips
2
HDWR
Standoff, 3/16" dia. x 3/8" long, round, 4-40 threaded
1
MISC
Wire, #26 enamel
3 ft.
MISC
KNB2 PC board, Elecraft P/N E100087
1
Assembly
i
The noise blanker board will be mounted directly above the K2's I.F. amplifier transistor,
Q22. To avoid shorts between the bottom of the noise blanker and Q22 (or Q22's heat sink), you must
trim all noise blanker component leads to 1/16" (1.5 mm) or less.
Flush-cutters
are ideal for this. If
you don't have flush-cutters, trim leads close to the board
before
soldering.
Install all of the capacitors in the order shown in the parts list (C16, C4, C3, etc., up to but not
including C15). Bend the leads of each capacitor slightly to hold it in place. Trim the leads before soldering
or flush-cut afterward, as described above.
Install electrolytic capacitor C15 with its positive (+) lead inserted into the hole labeled "+".
Install Diodes D2 and D3. These are glass-bodied diodes and should be handled carefully. Orient the
banded end of each diode as indicated by its PC board outline.
Install all of the transistors (Q1-Q7). (
Note:
Be sure
not
to install a transistor at the location labeled
"U2," near the standoff hole. U2 is a voltage regulator IC.) Transistors should be mounted so that their
bodies are approximately 1/8" (3 mm) above the PC board. Re-check each part number against the list
before soldering.
Install resistors R8, R9, and R10, which are located on the top side of the board near U1 (MC1350).
i
In the following step, you'll install several resistors on the bottom side of the PC board. Since
components on the top side of the board are very closely spaced, you should solder the bottom-mounted
resistors on the bottom side. This will prevent damage to top-mounted components. To avoid difficulty in
trimming resistors leads, pre-trim the leads to the correct length before mounting.
Install the remaining resistors, all of which are on the bottom side of the board. To ensure that
clearance is maintained for the I.F. amplifier (RF board, Q22), keep the resistors flush against the bottom of
the board. Pre-trim the leads and solder on the bottom side as explained above.
