Communication Concepts EB63A Construction Hints - Manual (Page 2)

Install the 1N4001 diode D1 as shown. Observe the polarity..!! The banded end is the
cathode.
Position the transformer T2 on the PC board as shown in the Engineering Bulletin. The
transformer must be installed with the wide gap on the input end placed down on the PC
board. The split-end of the transformer goes toward the center of the PC board. Solder
the split-ends (two places) and the opposite solid end to the PC board with a fillet of
solder (make sure the transformer is held flat against the PC board). Trim the Teflon
insulated secondary windings of T2 for a proper length for mounting into their respective
mounting holes on the PC board. Then trim about ¼” of the insulation off the wire leads.
Install the leads into their proper mounting holes and solder to the PC board.
The input transformer T1 is mounted next. Trim the wire leads to the proper length to
mount on the PC board. Strip ¼” of the insulation from the wire leads. Mount the
transformer to the PC board with the split ends toward the RF transistors. Solder the
transformer to the PC board similar to T2. Solder the wire leads to the PC board.
Install RFC1 as shown on the component layout. RFC1 is composed of ten beads on a
piece of buss wire bent into a “U” shape. The buss wire is soldered through its
respective mounting holes near the edge of the PC board.
Install the 1 uF tantalum capacitor C6 on top of the PC board as shown in the
component layout.
Install the 10uF electrolytic capacitor C5 on top of the PC board as shown in the
component layout.
Install the .001uF disc capacitor C7 on top of the PC board as shown in the component
layout.
Install the 470pF disc capacitor C11 in its proper location as shown in the component
layout. Clip off the excess leads.
Install the 22uF electrolytic capacitor C12 in its proper location as shown in the
component layout. Clip off the excess leads. This capacitor is used to increase the
relay hold time when SSB mode is used. If a longer delay is desired, increase the size
of C12 to 100 uF for approximately 1-½ seconds of delay. An external switch (not
supplied) can be used to activate or ground on side of the capacitor to increase the
delay time.
Install the 18pF mica capacitor C2 and the 24pF mica capacitor C10 on top of the PC
board as shown in the component layout.
Install the 33pF mica capacitor C1 on top of the PC board as shown in the component
layout.
Install the 910pF mica capacitor C20 on top of the transformer T2 and the 1100 mica
capacitor C21 on top of the transformer T1. The leads of the capacitors are soldered to
the split ends of the transformers and the capacitors lay over the top of the transformers.
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