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Procedure:
1. Turn OFF the noise filter switch (S401) on the TX-BASE board.
2. Set the channel select switch (S402) on the TX-BASE board to CH2.
3. Enter 1 kHz 316 mVrms signal only to the Lch (J403) on the TX-BASE board.
4. Using on AC voltmeter, measure the voltage of IC403 pin 1 on the TX-BASE board to check that it is 220 mVrms to 250 mVrms.
5. If out of the specified value, adjust the voltage by rotating RV401 on the TX-BASE board so as to attain 235 mVrms.
Adjustment Location: TX-BASE board (See page 6.)
2-3. Subcarrier Level and Frequency Check and Adjustment
Preparation:
AUDIO IN (J403: Lch)
AF OSC
1 kHz 316 mVrms
TMR-RF930
ATT
+
+
+
Trans-
–
–
–
mitter
600 Ω
[TX-BASE board] – C0nductor Side–
Procedure:
1. Turn OFF the noise filter switch (S401) on the TX-BASE board.
2. Set the channel select switch (S402) on the TX-BASE board to CH2.
3. Enter 1 kHz 316 mVrms signal only to the Lch (J403) on the TX-BASE board.
4. Connect a frequency counter and an oscilloscope between emitter of Q409 and ground on the TX-BASE board.
5. Turn off the input to the Lch on the TX-BASE board. (If the input is not turned off, the subcarrier is modulated and it cannot be
measured.)
6. Check that the frequency counter indicates 48 kHz to 52 kHz.
7. If out of the specified value, adjust the frequency by rotating RV405 on the TX-BASE board so as to attain 50 kHz. Also, check that the
waveform on oscilloscope is as shown below.
3.6 Vp-p ± 0.2 V
Note:
As the transmitter turns off automatically about one minute after the input to Lch of transmitter was turned off, checking and adjustment must be performed
within one minute. If it turned off automatically, again turn on the input to Lch to turn on the transmitter automatically, then turn off the input to Lch and
perform checking and adjustment.
oscilloscope
frequency counter
+
OUT
–
coaxial cable
– 5 –
Adjustment Location:
[TX-BASE board] – Component Side –
RV401
Degree of
Modulation of
Subcarrier (L – R)
Adjustment
RV404
Degree of
Modulation of
Main Carrier (L + R)
Adjustment
(Please refer to
MDR-RF930
Service manual for
this adjustment)
IN
RV405
Subcarrier Level
and Frequency
Adjustment
RV402
RV403
J402
J403
(Rch)
(Lch)
– 6 –
Transmission
Frequency
Adjustment
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