Elecraft K1 - Manual (Page 23)

22
E
LECRAFT
Visual Inspection
Using the parts placement drawings in Appendix F, re-check
the orientation of the LEDs (D1 and D2), LCD (DS1), and all ICs.
Examine both sides of the PC board closely for solder bridges,
cold solder joints, or unsoldered components.
Resistance Checks
Set both potentiometers to their mid-points.
The resistance measurements shown below can all be made
from the top side of the board. The (-) lead of your DMM should be
connected to the ground jumper (
) at the left side of the board.
Test Points (+) Resistance
DS1 (LCD) pins 1-24 > 100 k
J1 pin 6 > 100 k
J1 pin 7 > 100 k
J1 pin 8 > 100 k
J1 pin 10 90-200 k
J1 pin 12 > 100 k
J1 pin 15 < 50 k
J1 pin 16 15-18 k
J1 pin 19 > 100 k
Front Panel Final Assembly
Cut three 1.25" (32 mm) lengths of hookup wire. Remove 1/4"
(6 mm) of insulation from both ends of each wire.
Locate the 10-turn potentiometer, R1. Look closely at
Figure 5-9, which shows the positions of the three lugs. The lugs
may be labeled 1, 2, and 3, or S, CW, and CCW. 10-turn
potentiometer labeling can be confusing, so use the drawing to
identify the lugs. Your potentiometer may be either of the two
types shown.
CW
S
CCW
3
2 1
1 2 3 R1 1 2 3 R1
Type 1 Type 2
Figure 5-9
Attach the prepared wires to the three lugs Each wire should be
wrapped around its lug, leaving the other end free. (Do not solder
yet.)
R1’s plastic body can be damaged if you apply too much heat
to the lugs. Solder the three lugs, limiting soldering time to about
two seconds each.
Insert R1 through the large round hole in the Front Panel
board, rotating it into approximately the position indicated above.
Make sure that none of the lugs are touching the PC board.
Near the large hole in the board, you'll find three pads for R1's
leads (labeled 1, 2, and 3). Referring to Figure 5-9, insert the
potentiometer's wires into their corresponding holes. Do not
solder yet.
i
Caution: If the leads of R1 are not connected to the
correct pads, the potentiometer is very likely to be damaged.
Re-check the connections, then solder R1's leads on the top
side of the board. Avoid touching nearby parts with the iron.