16 MAINTENANCE
INTERNAL ADJUSTMENTS
1
REFERENCE FREQUENCY CALIBRATION
2
Note:
The transceiver is adjusted at the factory prior to shipping.
Unless necessary, DO NOT perform this adjustment.
If you have installed the optional SO-2 unit, you cannot perform
this adjustment.
3
1 Set the following on the transceiver:
•
Mode: CW
4
•
AF control: Center
•
Menu No. 20 (CW RX pitch): 800 Hz
•
IF SHIFT control: Center
5
•
Receive bandwidth {page 38}: 600 Hz
•
RIT function: OFF
•
Break-in function (VOX): OFF
6
2 Remove the bottom case (8 screws) from the
transceiver.
3 Remove the protective cover installed on the PC
board (6 screws).
7
8
9
10
4 Tune in a standard frequency station such as WWV
or WWVH at, for example, 10.000 or 15.000 MHz.
•
Adjust the Tuning control so that the display
11
reads the exact frequency of the station.
•
You should hear a beat tone of approximately
800 Hz.
•
For 800 Hz:
12
f
= (f
/20.000 x f
af
display
where f
reference
reference frequency
13
5 Close your CW key and you will hear a transmit
sidetone of approximately 800 Hz.
•
This sidetone produces a double beat tone when
14
it combines with the received signal.
•
Adjust the AF control to hear the double beat
clearly.
•
For 800 Hz:
15
f
= 800 Hz 50 ppm (= 800 0.04 Hz)
sidetone
where f
reference
reference frequency
16
64
) + 800 Hz
reference
is the shift from the 20 MHz
is the shift from the 20 MHz
6 Adjust the TC500 trimmer to minimize the frequency
difference between the received 800 Hz tone and
the 800 Hz sidetone.
7 Re-install the protective cover on the PC board
(6 screws).
8 Re-install the bottom case (8 screws).
ACCESSING THE INTERNAL FUSE
1 Remove the top case (8 screws) from the
transceiver.
2 Remove the 12 screws that fasten the inner cover to
the chassis.
3 Open the inner cover.
•
Be careful not to damage the speaker cable
connected to the PC board.
TC500
Fuse (4A)