Elecraft KXB30 - Manual (Page 7)

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Remove the adhesive backing from the rubber bumpers and install them as shown in Figure 2 a. If the
bumpers don't sit flat on the board, make sure all of the leads have been trimmed.
Hold the KX1 so you can look at the edge of the installed KXB30 board as shown in Figure 2 b. All
leads must be trimmed well below the height of the two rubber bumpers.
(a) (b)
Figure 2
Re-install the KX1 top cover, 3 screws, and VFO knob. Leave the bottom cover off so the trimmer
capacitors can be aligned.
Alignment and Test
Insert a millimeter, preferably a DMM (digital multimeter), in series with the KX1's external power
jack (J1) and a fused, 8 to 14-volt DC power source.
Select a 200 or 300 mA full-scale range on the meter.
Turn on the power supply and the KX1. If the KX1 LED display doesn't come on, turn off power
immediately and check resistance at the collector of the PA transistor (Q6, 12 V line), as well as pin 1 of
the MCU (5 V line) and pin 6 of U3 (TC4427, 6 V line). If any of these reads a low resistance (less than
500 ohms), you may have a short, possibly due to installation of the KXB30.
The milliammeter should show about 34 to 37 mA with the LED timed out. If the current is much
higher that this, it could again indicate a short or component problem on the KXB30. Note: If necessary,
use the
L E D menu entry to set the timeout below infinite ( I N F ) to allow it to turn off for this current
measurement. When editing the L E D menu entry, turning the VFO knob counter-clockwise will reduce the
timeout period to as low as 5 seconds ( t 0 5 ).
In the menu, set the B 3 0 parameter to O N , then exit the menu. 30 meters will now appear after 40
meters when you tap B A N D quickly two or more times.
The KXB30 introduces some stray capacitance. To account for this, re-align the KX1's receiver on 20
and 40 meters as described in the KX1 Owner's manual (Alignment and Test, Part II).