TM 1-1510-218-10
3C-44
audio signals are applied to the audio control panel.
The ADF receivers are powered through two 2-ampere
circuit breakers, placarded ADF #1 and #2, located on
the overhead circuit breaker panel, Figure 2-16.
b. ADF Control Unit (KFS-586A) Controls,
Indicators, and Functions. Refer to Figure 3C-19.
1. Frequency Display
2. Frequency Transfer Switch
3. Tuning Knobs
4. MODE Switch
5. CHAN Switch
6. OFF /VOL / PUSH Control
Figure 3C-19. ADF Receiver Control Unit
(KFS-586A)
(1) Frequency Display. Liquid crystal digital
readouts provide a continuous display of both the
active frequency (top line) and standby frequency
(bottom line, placarded SBY) when the system is in
the frequency mode. System mode is controlled by
the CHAN push-button switch. When the system is in
the channel mode, the upper digital display reads CH
(channel) and a channel number (1 through 9), while
the lower digital readout displays the frequency of the
displayed channel number. When the system is in the
program mode, the upper digital display will read P
(program) and a channel number, while the lower
digital display will read the frequency of the displayed
channel. The operating mode (ANT, ADF, and BFO)
is also shown in the display. A small X located on the
left of the active display informs the operator that the
bearing information is invalid. Display brightness is
controlled by a dimming control, placarded VHF / NAV
/ ADF, located right of the altitude alert indicator on the
instrument panel.
(2) Frequency
Transfer
Switch.
The
frequency transfer switch is a momentary push-button
switch placarded with a two-headed vertical arrow,
located to the right of the digital display.
(a) Standby Entry Mode. Pressing the
frequency transfer switch with the unit in the standby
entry mode causes the frequency displayed in the
active digital display to interchange with the frequency
shown in the standby digital display.
(b) Active Entry Mode. While the unit is
in the standby entry mode or the channel mode,
holding the transfer switch pressed for longer than
2 seconds will cause the unit to enter the active entry
mode. While in the active entry mode, momentarily
pressing the transfer switch will return the unit to the
standby entry mode.
(c) Channel Mode. When the unit is in
the channel mode, pressing the transfer switch will
return the unit to the frequency standby mode. The
channel frequency will become the new active
frequency and the last active frequency will become
the new standby frequency. If the unit was in the
active entry mode prior to entering the channel mode,
pressing the transfer switch will return the unit to the
standby entry mode.
(3) Tuning Knobs. Two concentric tuning
knobs, located on the right side of the ADF receiver
control panel, are used to set the frequency or channel
shown on the digital display, depending upon the
mode of operation being used.
(a) Frequency Standby Entry Mode.
When the unit is in the frequency standby entry mode,
the larger concentric knob is used to increase or
decrease the hundreds kHz digits (1 to 17), of the
standby digital display. When the larger concentric
knob is turned so as to increase the digits above 17,
the display will start over at 1. Conversely, when the
knob is turned so as to decrease the digits below 1,
the display will start over at 17. When the control unit
is in the standby entry mode or in the program mode
when the frequency is flashing and the larger tuning
knob is turned so as to increase the hundred kHz
digits above 17, the display will change to 2182 kHz. If
the larger concentric knob is turned so as to increase
the frequency above 2182 kHz, the hundred kHz digits
will start over at 1. The smaller concentric knob is
