Sony HCD-D390 - Compact Audio And Video System, Service Manual

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FM Polar Adjustment (East European, CIS model only)
Connection 1:
Carrier frequency: 69 MHz
Output level :
1 mV (60 dB
µ
) (at 75
Ω
open)
Modulation: AUDIO 1 kHz, 10 kHz deviation
FM antenna
terminal (75
Ω
)
75
Ω
coaxial
set
FM RF SSG
Connection 2:
Carrier frequency: 69 MHz
Output level :
1 mV (60 dB
µ
) (at 75
Ω
open)
Modulation: AUDIO 31.25 kHz, 10 kHz deviation
(EXTERNAL MODULATION)
FM antenna
terminal (75
Ω
)
75
Ω
coaxial
set
FM RF SSG
AF OSC
external
modulation
terminal
Audio 31.25 kHz
Adjustment Location: TCB board
[TCB BOARD] (Conductor Side)
IC17
Level meter
Frequency counter
TP1701
(FILTER)
TP1702
(VCO)
IC1701
RV1702
VCO
RV1701
Sub Carrier
Level
L1701
CT1701
Sub Carrier Peak
[TCB BOARD] (Component Side)
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 (VCO) 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 connected
to TP1701 (FILTER) becomes maximum. (SUB CARRIER
PEAK Adjustment)
9. Adjust the RV1701 so that the level at the moment becomes 14
dB higher value than the level recorded in step 4. (SUB CAR-
RIER LEVEL Adjustment)