MHC-W555, STR-W555 - Sony Audio Service Manual (repair manual). Page 11

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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 con-

nected 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 con-

nected to TP1701 (FILTER) becomes maximum.
Then adjust the CT1701 so that the reading of the level meter
connected to TP1701 (FILTER) becomes maximum. (SUB CAR-
RIER 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)

[TCB BOARD] (Component Side)

Adjustment Location: TCB board

[TCB BOARD] (Conductor Side)

FM antenna 
terminal (75 

Ω

)

FM RF SSG

75 

Ω

 coaxial

Carrier frequency: 69 MHz
Output level:

1 mV (60 dB

µ

) (at 75 

Ω

 open)

Modulation:

AUDIO 1 kHz, 10 kHz deviation

set

FM antenna 
terminal (75 

Ω

)

Audio 31.25 kHz

external
modulation
terminal

FM RF SSG

AF OSC

75 

Ω

 coaxial

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)

set

frequency counter

level meter

TP1701
(FILTER)

TP1702
(VCO)

IC1701

L1701

CT1701

Sub Carrier Peak

RV1701
Sub Carrier
Level

IC1701

RV1702
VCO