Read Sony MHC-W77AV / STR-W77 Service Manual online
– 6 –
SECTION 3
ELECTRICAL ADJUSTMENTS
SW Control Voltage Adjustment
(Frequency Coverge Adjustment)
(E3, EA, MY, SP, HK, JE model)
(Frequency Coverge Adjustment)
(E3, EA, MY, SP, HK, JE model)
Setting :
Band : SW
Procedure :
1. Connect digital Voltmeter to diode D1 center lead and ground.
2. Adjust for a following value reading on digital Voltmeter.
1. Connect digital Voltmeter to diode D1 center lead and ground.
2. Adjust for a following value reading on digital Voltmeter.
Set frequency
Adjustment
part
Reading on digital
voltmeter
SW
5.95MHz
T2
1.2Vdc
17.9MHz
CV2
8.5Vdc
SW Tracking Adjustment
(E3, EA, MY, SP, HK, JE model)
(E3, EA, MY, SP, HK, JE model)
Setting :
Band : SW
+
–
AM RF signal
generator
generator
AM ANTENNA terminal
SPEAKER terminal
Modulation : 400Hz
30% modulation
set
VTVM
Procedure :
Adjust for maximum reading on VTVM.
Adjust for maximum reading on VTVM.
Set frequency
Adjustment
part
SW
7MHz
T1
17MHz
CV1
r
Repeat the procedures is each adjustment several times, and the
frequency coverage and tracking adjustment should be finally done
by the trimmer capacitors.
by the trimmer capacitors.
Adjustment Location : TCB board
Precautions in Repairing
Note. 1 :
The adjustment should be performed in the publication.
(MW
(MW
n FM n SW)
Note. 2 :
As a front-end (FE1) is difficult to repair if faulty, replace
it with new one.
it with new one.
r
Abbreviation
AUS : Australian
AR
: Argentine
EA
: Saudi Arabia
HK
: Hong Kong
SP
: Singapore
JE
: Tourist
MY
: Malaysia
TH
: Thailand
CND : Canadian
E2
E2
: Tuner sections SW BAND do not exist.
E3
: Tuner sections SW BAND exist.
MW SECTION
MW Tuned Indication Lighting Level
Setting :
Band : MW
Band : MW
set
AM RF signal
generator
generator
loop antenna A
loop antenna B
Carrier frequency : 999kHz (at 9kHz step)
1,050kHz (at 10kHz step)
Procedure :
1. Set loop antenna A so that the loop antenna B input level becomes
1. Set loop antenna A so that the loop antenna B input level becomes
55dB
µ
/m (0.6mV/m)
2. Tune the set to 999kHz or 1,050kHz.
3. Adjust RV41 so that the TUNED indicatior goes on.
3. Adjust RV41 so that the TUNED indicatior goes on.
FM SECTION
FM Tuned Indication Lighting Level
Note :
Note :
Always make the tuning level adjustment first.
(Since it affects the FM tuning level.)
Setting :
Band : FW
Band : FW
FM RF stereo signal
generator
generator
75
Ω
coaxial
FM ANTENNA terminal
set
Carrier frequency : 98MHz
Modulation
Modulation
: OFF
Output level
: 0.018mV (25dB )
µ
Procedure :
1. Tune the set to 98MHz.
2. Adjust RV42 so that the TUNED indicator goes on.
1. Tune the set to 98MHz.
2. Adjust RV42 so that the TUNED indicator goes on.
Click on the first or last page to see other MHC-W77AV / STR-W77 service manuals if exist.