ELECRAFT K 2 Owner's Manual page 73

K2 Manual 1/24/99 V.XC ©1999 Elecraft
Locate the "binocular" (2-hole) ferrite core for T4. Wind 2 turns
of #22 Teflon-insulated hookup wire (5", 13cm) through the core as
shown in Figure 6-5. This forms the 1–2 winding.
Cut and strip the two leads using the lengths shown.
1
2
1/2" (13mm)
7/8" (22mm)
Figure 6-5
Wind a 3-turn winding (3–4) on top of the 1-2 winding, but with
the wire starting and ending on the opposite side (Figure 6-6). Use 7"
(18cm) of #22 Teflon-insulated hookup wire.
Figure 6-6
Before installing T4, verify that the screws holding the 2-D
fastener beneath it are tightened, and that #4 internal-tooth lock washers
were used. It is important that these screws not come loose sometime
after T4 has been installed.
Install T4 to the right of T3, inserting leads for the 1–2 and 3–4
windings into their matching numbered holes. T4 should rest directly on
top of the screws that secure the 2-D fastener beneath it. T4 should also
be parallel to the board, not tilted to one side. Pull the leads taught on
the bottom and bend them to hold the transformer in place. Do not
solder T4 yet.
Use two 2" (5cm) lengths of bare hookup wire to form the 5–6 and
7–8 windings on T4 (Figure 6-7). Route the links through the core first,
then bend them down and insert them into their numbered holes and
solder. Do not solder the link windings yet.
3
Adjust the windings of T4 as needed so that the transformer is
4
positioned directly above its component outline. Pull the leads tight on
the bottom, then solder.
Inspect all four transformers in the transmitter area closely, on
both top and bottom, for shorts or cold solder joints.
5
8
Figure 6-7
71
6
7