Elecraft K2 Owner's Manual - Manual (Page 58)

E
LECRAFT ® 57
Install T5 as shown by its component outline in the synthesizer
area of the board. Figure 6-17 shows how the 1–2 and 3–4 windings
are oriented with the numbered pads. (Also shown are the nylon
washer and screw, which will be installed in the next step.) Pull T5’s
leads taut on the bottom of the board, but do not solder yet.
Secure T5 to the board as shown in Figure 6-17 using a 3/8" (9.5
mm) diameter nylon washer, 1/2" (12.7 mm) long nylon 4-40 screw,
and a #4 nylon nut. Tighten the nylon nut just enough to hold the
assembly in place. Do not over-tighten as this will strip the threads.
Solder T5, checking for good solder joints as before.
3
4
2
1
Figure 6-17
T7 is a toroidal transformer wound on a 3/8" (9.5 mm) diameter
ferrite core (dark gray, FT37-43). T7’s orientation and windings will
appear similar to Figure 6-18. Wind T7’s 3–4 winding first, using 20
turns of red enamel wire (20", 51 cm). (The drawing shows 14 turns.)
Wind T7's 1–2 winding using 5 turns of green enamel wire (6",
15 cm). Strip and tin the leads of both windings.
1 2
4 3
Figure 6-18
Install T7 as shown by its component outline near the front-right
corner of the board, with the windings oriented as shown in Figure
6-18. Pull the leads taut on the bottom and solder.