ELECRAFT K2 - Page 46

ELECRAFT 45
Plug the frequency counter probe assembly into P6, which is at
the far left end of the Control board (as viewed from the front of
the transceiver). The connector can only be plugged in one way.
Turn on the K2 and tap M E N U to bring up the menu, then
scroll to the C A L menu entry. Hold
E D I T , then scroll the C A L
parameter until the display shows C A L F C T R . Hold
E D I T again
to activate the frequency counter function of the C A L sub-menu.
The LCD should show 0 0 0 0 . 0 0 . (The frequency counter circuitry
is sensitive, so it may pick up a stray signal and show it on the
display.)
To test the counter, you can read the frequency of the 4 MHz
oscillator on the Control board. Touch the counter probe tip to the
left side of trimmer capacitor C22, which is just below the 18C452
microcontroller. The LCD should now read very close to
4 0 0 0 . 0 0 .
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Remove the frequency counter probe.
Audio Amplifier and Tone Generator Test
Plug in a pair of low-impedance (4 to 32 ohm) headphones,
stereo or mono.
Tap M E N U and scroll to the sidetone level menu entry
(S T L ). Hold
E D I T to activate the sidetone. You should now hear a
clean 600-Hz audio tone. Turning the VFO knob should vary the
volume.
Notice that turning the AF GAIN control does not affect the
sidetone volume. The sidetone is injected into the AF amplifier
after the volume control, so AF GAIN affects only the receiver
volume.
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This is not a valid indication of how well the 4 MHz oscillator is
calibrated, since this oscillator is used as the reference for the frequency
counter itself. The 4 MHz counter will be calibrated in a later step.
Tap M E N U to turn off the sidetone, then scroll up to the
sidetone pitch menu entry (ST P) using the VFO knob or by
tapping the
B A N D + switch. The display will show
S T P 0 . 6 0
This indicates that the sidetone pitch is set for 0 . 6 0 kHz (600 Hz).
Hold
E D I T to turn on the sidetone, then vary the VFO knob. The
pitch of the sidetone should change to match the display.
Keyer
In the following steps you’ll test the keyer (audio tone generation
only). This tests the keyer jack, speed control, and potentiometer
read circuits, including the A-to-D converter on the
microcontroller.
Tap M O D E until C is displayed at the right end of the LCD,
indicating CW mode.
Plug a keyer paddle into the key jack. The plug must be stereo
(2 circuit). A mono plug will key the transmitter continuously. (A
mating stereo plug for the keyer jack is supplied with the kit.)
Using the menu’s I N P entry, set up the keyer input for either
P D L n or P D L r as described previously.
Adjust the KEYER control. As soon as you turn it, the display
should show the keying speed (approx. 9-50 WPM).
While listening with headphones, test the keyer paddle to
verify that both dot and dash are working.
Note: No sidetone will be generated when LSB or USB mode is
selected (L or U).