Elecraft KIO2 - Manual (Page 10)

10
Remove the screws that hold the Control board to the Front Panel board. If you have the KAF2 audio
filter installed, it must be unplugged first (after removing the screw on the left side).
Extract the Control board using the long-handled Allen wrench (see page 40 of the K2 manual).
If you received the revision 2.01 (or later) K2 firmware as an upgrade, and have not yet installed it,
you should do so now. Follow the steps in the K2 Revision 2 Firmware manual.
Locate 2-pin connector P5, in the upper left-hand corner of the Control board near switch S1 (top side
of the board). Trim 0.1" (2.5 mm) off both pins of P5. This will prevent shorts to the AUX2 board.
Locate the Control board revision letter, at the bottom right-hand corner near P3 (top side of the
board). If your Control board is rev. A (or XC, used during K2 field test only), you will need to modify it.
(If your board is rev. B or later, skip the next four steps.) Figure 5 shows the bottom side of the Control
board, where most of the modifications will be made. One trace will be cut (on the top side of the board).
U6
U8
40 25
P4
Q5
1
1
Cut trace on top side
Jumper, 4"
Jumper, 3/4"
(to pin 4 of U8,
not to RP7)
.001 µF
B ottom view of Control b oard
Figure 5
The trace between Q5-gate and U6 pin 25 must be cut as shown above. This trace is located on the
top side of the Control board. Once you have located the trace, use a sharp tool such as an X-acto knife to
make two small cuts near the location marked with an "X". Press down with the tip--don't draw the knife
across the trace, since you may slip, cutting adjacent pads or traces. Next, pry up and remove the small
segment between the cuts. Examine the trace closely to make sure the cut segment is completely removed.
Cut a 3/4" (19 mm) length of the supplied green-insulated hookup wire, and remove 1/8" (3 mm) of
insulation from each end. Solder this jumper on the bottom of the board, between Q5-gate and U8 pin 4, as
shown above. Make sure the jumper doesn't contact adjacent pads or component pins.
Solder a .001 µF capacitor ("102") across P4, pins 1 and 5. (Listed as Ctxd in the parts list.)
Prepare a 4" (10 cm) jumper using the green hookup wire. Solder it between U6 pin 25 and P4 pin 1
on the bottom side of the board (pin 1 is the round pad). Make sure the jumper doesn't touch adjacent pins.