DOWNLOAD Sony MHC-W77AV / STR-W77 Service Manual ↓ Size: 231.92 KB | Pages: 29 in PDF or view online for FREE

MICROFILM

US  Model

Canadian  Model

E  Model

Australian  Model

Tourist  Model

(REAR)
15 W + 15 W
(8 ohms at 1 kHz, 5% THD)

EXCEPT US model :

(FRONT)
120 W + 120 W
(6 ohms at 1 kHz, 5% THD)
(CENTER)
30 W (8 ohms at 1 kHz, 5% THD)
(REAR)
15 W + 15 W
(8 ohms at 1 kHz, 5% THD)

Inputs

VIDEO/MD IN (phono jacks) :

voltage 250 mV/450 mV
impedance 47 kilohms

MIX MIC (phono jacks) :

sensitivity 1 mV/450 mV
impedance 10 kilohms

Outputs

VIDEO/MD OUT (phono jacks) :

voltage 250 mV
impedance 1 kilohms

PHONES (stereo phono jacks) :

accepts headphones of 8 ohms or more

FRONT SPEAKER :

accepts impedance of 6 to 16 ohms

CENTER SPEAKER :

accepts impedance of 8 to 16 ohms

REAR SPEAKER :

accepts impedance of 8 to 16 ohms

SUPER WOOFER :

voltage 250 mV impedance 1 kilohms

– Continued on page 2 –

With 6 ohm loads, both channels driven, from 40–20, 000 Hz; rated 100 watts
per channel minimum RMS power, with no more than 0.9 % total harmonic
distortion from 250 milliwatts to rated output. (US model)

FM stereo, FM/AM superheterodyne tuner

FM tuner section

Tuning range

EXCEPT Tourist model :
   87.5–108.0 MHz
Tourist model :
   76.0–108.0 MHz

Antenna

FM lead antenna

Antenna terminals

75 ohm, unbalanced

Intermediate frequency

10.7 MHz

AM tuner section

Tuning range

US, Canadian, E2, Argentine, Australian,
Thailand model :
    AM : 530–1,710kHz (10kHz)
              531–1,710kHz (9kHz)
E3, Saudi Arabia, Hong Kong, Singapore,
Malaysia, Tourist model :
    MW : 531–1,602kHz (9kHz)
    SW : 5.95–17.90MHz (9kHz)

Antenna

AM loop antenna, External antenna terminals

Intermediate frequency

450 kHz

Continuous RMS power output

US model :

(FRONT)
100 W + 100 W
(6 ohms at 40–20,000 Hz, 0.9% THD)
120 W + 120 W
(6 ohms at 1 kHz, 5% THD)
(CENTER)
30 W (8 ohms at 1 kHz, 5% THD)

STR-W77 is RECEIVER section in
MHC-W77AV.

– 2 –

Specifications ................................................................................. 1

.............................................................................. 4

.......................................................................... 5

......................................... 6

.................................. 8

5-1. Printed Wiring Boards – Main Section– ......................... 12
5-2. Schematic Diagram – Main Section– ............................. 17
5-3. Schematic Diagram – Panel Section– ............................. 23
5-4. Printed Wiring Boards – Panel Section– ........................ 27
5-5. Schematic Diagram – TCB Section–

(US, CND, E2, AR, AUS, TH model) ............................ 29

5-6. Printed Wiring Boards – TCB Section–

(US, CND, E2, AR, AUS, TH model) ............................ 31

5-7. Printed Wiring Boards – TCB Section–

(E3, EA, MY, SP, HK, JE model) ................................... 32

5-8. Schematic Diagram – TCB Section–

(E3, EA, MY, SP, HK, JE model) ................................... 33

6-1. Chassis Section ............................................................... 35
6-2. Front Panel Section ......................................................... 37

.............................................. 38

Power requirements

US, Canadian model : 120 V AC, 60 Hz
Australian model : 240 V AC, 50/60Hz
Thailand model : 220 V AC, 50/60Hz
Other models :
110-120 V/220-240 V AC adjustable, 50/60 Hz

Power consumption

EXCEPT Canadian model : 260 watts
Canadian model : 350 VA

Dimensions

Approx. 280 x 205 x 345 mm (11x
8

1

/

16

 x 13

9

/

16

 in.) (w/h/d)

Mass

Approx. 6.4 kg (14 lb 2 oz)

Design and specifications are subject to change without notice.

• Never reuse a disconnected chip component.
• Notice that the minus side of a tantalum capacitor may be damaged

by heat.

!

!

!

4-980-659-0

π

    US

4-980-659-1

π

    Canadian

4-980-659-2

π

    E, Saudi Arabia, Argentine, Torist

4-980-659-3

π

    Australian

4-980-659-4

π

    Hong Kong

4-980-659-5

π

    Malaysia, Singapore

4-980-659-7

π

    Thailand

– 3 –

After correcting the original service problem, perform the following
safety check before releasing the set to the customer :
Check the antenna terminals, metal trim, "metallized" knobs, screws,
and all other exposed metal parts for AC leakage. Check leakage as
described below.

The AC leakage from any exposed metal part to earth ground and
from all exposed metal parts to any exposed metal part having a re-
turn to chassis, must not exceed 0.5mA (500 microampers).
Leakage current can be measured by any one of three methods.
1.

A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturers’ instructions to use these
instruments.

2.

A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.

3. Measuring the voltage drop across a resistor by means of a VOM

or battery-operated AC voltmeter. The “limit” indication is 0.75V,
so analog meters must have an accurate low-voltage scale. The
Simpson 250 and Sanwa SH-63Trd are examples of a passive VOM
that is suitable. Nearly all battery operated digital multimeters that
have a 2V AC range are suitable. (See Fig. A)

        

Earth Ground

Fig. A.  Using an AC voltmeter to check AC leakage.

AC 
Voltmeter
(0.75V)

0.15   F

µ

1.5k

Ω

To Exposed Metal
Parts on Set

– 4 –

This section is extracted from
instruction manual.