Sony HCD-GRX9000 Service Manual page 17

FM Polar Adjustment
Connection 1:
FM RF SSG
75 Ω coaxial
Carrier frequency : 69 MHz
: 1mV (60dB µ ) (at 75 Ω open)
Output level
Modulation : AUDIO 1 kHz, 10kHz deviation
Connection 2:
AF OSC
FM RF SSG
Audio 31.25 kHz
external
modulation
terminal
Carrier frequency : 69 MHz
: 1mV (60 dB µ ) (at 75 Ω open)
Output level
Modulation : AUDIO 31.25 kHz, 10 kHz deviation
(EXTERNAL MODULATION)
Adjustment Location :
[TCB BOARD] (Component Side)
TM1
IFT41
IC41
CN1
set
FM ANTENNA terminal
(75 Ω )
75 Ω coaxial
set
FM ANTENNA terminal
(75 Ω )
RV41
MW Tuned Level
Adjustment
RV42
FM Tuned Level
Adjustment
L1701
Sub Carrier Peak
Adjustment
RV1701
Sub Carrier Level
Adjustment
CT1701
Sub Carrier Peak
Adjustment
RV1702
VCO Adjustment
Procedure :
1. Set the modulation of FM RF SSG to AUDIO 1 kHz, 10 kHz
deviation according to "Connection 1".
2. Tune the set to 69 MHz.
3. Adjust the RV1702 so that the reading of frequency counter
connected to TP1702 becomes within 31.25 kHz ± 0.05 kHz.
(VCO Adjustment)
4. Then record the reading of the level meter connected to TP1701
5. Set the modulation of FM RF SSG to AUDIO 31.25 kHz, 10
kHz deviation according to "Connection 2".
6. Tune the set to 69 MHz.
7. Set the CT1701 to be mechanical center.
8. Adjust the L1701 so that the reading of the level meter con-
nected to TP1701 become maximum.
Then adjust the CT1701 so that the reading of the level meter
connected to TP1701 becomes maximum. (SUB CARRIER
PEAK Adjustment)
9. Adjust the RV1701 so that the level at the moment becomes
14dB higher value than the level recorded in step 4. (SUB CAR-
RIER LEVEL Adjustment)
[TCB BOARD] (Conductor Side)
Q1701
TP1701
(FILTER)
Q1702
TP1702
(VCO)
Q1703
– 17 –
level meter
+
–
frequency
counter
+
–