Electrical Adjustments - Sony HCD-EX770 Service Manual

Precautions in Repairing
If the front unit fails, it is difficult to repair the inner circuits, so
replace the entire front end unit.
The FM TUNED level must be adjusted after the AM TUNED
level adjustment has completed.
AM SECTION
AM Tuning Level Adjustment
Setting :
BAND switch : MW(AM)
AM RF
signal generator
30 % amplitude modulation by
400 Hz signal
Carrier frequency : 999 kHz (at 9 k step)
1,000 kHz (at 10 k step)
: 25 dB µ
Output level
Procedure:
1. Set loop antenna A so that the loop antenna B input level be-
comes 55 dBµ/m.
2. Tune the set to 999 kHz or 1,000 kHz.
3. Adjust RV1 so that the TUNED indicator goes on.
Adjustment Location : MAIN board.
FM SECTION
FM Tuning Level Adjustment
Setting :
BAND switch : FM
FM RF Stereo signal
generator
Carrier frequency : 98 MHz
Moduration : AUDIO 1kHz,75 kHz
deviation (100%)
: 26 dB µ (17.8 µ V)
Output level
Procedure:
1. Tune the set to 98 MHz.
3. Adjust RV2 so that the TUNED indicator goes on.
Adjustment Location : MAIN board.
SECTION 3

ELECTRICAL ADJUSTMENTS

loop antenna
loop antenna
supplied accessories
60 cm
set
FM antenna terminal
(75 Ω coaxial)
set
AM antenna terminal
field strength dB( µ V/m)=
RF SSG output level dB ( µ V/m)–26 dB
Adjustment Location :
[MAIN BOARD] – Component Side –
RV2
FM Tuning Level Adjustment
CN101
FE2
IC1
CN102
RV1
AM Tuning Level Adjustment
TM1