Beechcraft C-12C Operator And Technical Reference Manual page 270

TM 1-1510-218-10
1. Mode Display
2. USE Frequency Display
3. STBY/TIMER Display
4. Frequency Select Knobs
5. OFF/VOL Control Switch
c. Controls and Functions.
(1) Mode Display. Displays operating mode
the unit is in.
(2) USE Display.
which the system is tuned.
(3) STBY/TIMER Display. Displays standby
frequency, flight time, or elapsed time. The standby
frequency is placed in memory when either Flight Time
(FLT) or Elapsed Time (ET) mode is selected.
(4) Frequency
active/standby frequencies.
(a) Active
frequency is displayed in the left portion of the window
display. This frequency may be changed with the
concentric knobs when either time mode (FLT or ET)
is being displayed. To set the 10's digit, push the
small knob in and rotate it.
increment the digit. The digit will roll over at 9 to 0 and
roll under (when turning the knob counterclockwise) at
0 to 9. With the small knob pulled out, the 1's digit
may be set. Its operation is the same as for the 10's
digit.
Turning the large knob changes the l00's digit
and the 1000's digit. The 100's digit carries to the
1000's digit from 9 to 10 and borrows from 10 to 9.
The two digits roll over from 17 to 02 and under from
02 to 17, limiting the frequencies to the range or
200 kHz to 1799 kHz.
3A-28
Figure 3A-16. ADF Radio (KR 87)
Displays frequency to
Select Knobs. Selects
Frequency. The active
Clockwise rotation will
6. SET/RST Button
7. FLT/ET Button
8. FRQ Button
9. BFO Button
10. ADF Button
(b) Standby Frequency.
frequency is displayed in the right portion of the
display window when the FRQ message is displayed.
In this case, the standby frequency may be changed
with the frequency control knobs as desired. If the
standby frequency is not being displayed, it may be
called to the window by pressing the FRQ button.
Pressing this button when the standby frequency is
displayed causes the current standby and active
frequencies to be exchanged.
(5) OFF / VOL Control Switch. Rotating this
control switch clockwise out of detent turns the unit on.
Further rotation of the control switch increases volume.
(6) SET / RST Button. This button controls
the elapsed time. Time is reset back to zero each time
the button is pressed.
countdown mode, which is set by pressing the SET /
RST button for 2 seconds or until the ET display
begins to flash. With the ET flashing, the selector
knob will set any time up to 59 minutes, 59 seconds.
To start the elapsed time count down, press the SET /
RST button and the timer will start counting down. At
zero, the timer will begin to flash for 15 seconds and
then go to a solid display. While the FLT or ET is
displayed, the in use frequency may be changed with
the frequency control knobs.
The standby
The elapsed times have a