46 ELECRAFT
Setting the AGC Threshold
Make sure the RF GAIN control is rotated fully clockwise.
Locate potentiometer R1 on the Control board (right side, as
viewed from the front of the K2).
Set your DMM for DC volts.
Connect the (-) lead of the
DMM to one of the ground jumpers or to the K2 chassis ground.
Touch the (+) lead to pin 5 of U2 on the Control board. (U2 is
located just above trimmer R1. Pin 5 is the pin nearest diode D1.)
Adjust R1 for a reading of 3.80 volts on the DMM. This is the
suggested setting, but it can be adjusted later to suite the operator.
i
The S-meter must be realigned anytime the AGC
threshold setting is changed. S-meter alignment is covered
in the following steps.
S-Meter Alignment
Using the menu, select the C A L S L O function (S-meter
zero). Hold
E D I T a second time to activate it.
Turn the VFO knob until you see only the left-most segment
of the LED bargraph lit. Then turn the knob a bit more clockwise
until this LED just turns off.
Exit the C A L S L O function by tapping M E N U . Enter the
menu again and select C A L S H I (S-meter full-scale sensitivity).
Turn the RF GAIN fully counter-clockwise (minimum gain).
Adjust the VFO knob until you see segment 9 of the bar graph lit,
then turn it a bit more counter-clockwise until segment 10 just
turns on (right-most segment).
Turn the RF GAIN control back to its full clockwise position.
Exit the C A L S H I function by tapping M E N U .
Bargraph Current Test
In the following steps, you’ll test the current measurement circuit
by using the bargraph LEDs to establish a known current drain.
Enter the menu and verify that G R P H (LED bargraph mode)
is set to D O T , not to B A R or O F F .
Set the RF GAIN control for minimum gain. Segment 10 of
the LED bargraph should now be on if you have done the S-meter
adjustment as described above.
Using the menu, select the L C D menu entry. Change the
parameter from N I T E to D A Y . At this point you’ll see the LCD
backlight turn off, and segment 10 of the LED bargraph will
become much brighter.
Exit the menu and tap D I S P L A Y to switch to voltage/current
mode. Write down the voltage and current readings.
Use the menu to change the G R P H mode to B A R . All 10
segments of the LED should now be on.
Exit the menu and check the current. It should now be about
0.16 to 0.18 amps higher.
Use the menu to change G R P H to D O T , and L C D to N I T E .
i
The combination of L C D D A Y and G R P H B A R can
result in high peak current drain on receive. When operating from a
battery, D O T or O F F should be used to conserve power. More
information about conserving power is provided in the Advanced
Operating Features section.
To Next Page
Loading...
