Sony bm 77 service manual

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MANUAL

US Model
Canadian Model
AEP Model

UK Model

E Model

Recording system

Tape Speed
Fast winding lime
Frequency response

Speaker

Power output
input

Output

SPECIFICATIONS

rack 2£hannel monaural
(L channel for electronic index signals. a channel Ior souno signals)
4.3 cm/s (w. in./s), 2.4 cm/s (vs/.. in/s)
Approx, 2 min. 20 sec. Wllh Sony cassette 00-90
20075000 H1 (at 2.4 cm/s)
ZOO-3.000 Hz (a! 4.8 crn/s)
Approx. 5.7 cm (2% inches) die.
350 mW (BI 10% distortion)
TELEPHONE PICKUP (minljack)
Sensitivity 02 mV
Input impedance 1D kahms
EARPHONE (minijack)
for 8400-on earphones

CONTROL UNIT conneclor

Power requilemsnls

Power consumption
Dimensions

Weigh!
Supplied accessory

lcr Hu-ao or FS-15
9 v no
no [N 9 v jack accepts the supplied Ac power adaptor lor use on
120 V AC, 90 Hz (US, Canadian model)
220 V AC, 50 HZ (AEP, E model)
240 V AC, 50 H1 (UK model)
14 W (US, Canadian model) (with the supplled AC power adaptor)
13 w (AEF'. UK, E model) (with the supplied AC power adaptor)
Approx. 200 x 70 x 245 mm (w/h/d) (77/. x 27/. x 93/4 inches)
Including projecting pans and controls
Approx. L2 kg (2 to 1102)
AC power adapter (I)

Design and specifications subject to change wilhoul notice,

Model Name Using Similar Mechanism BM»88

Tape Transport Mechanism Type MB-88-59

SAFETY-RELATED COMPONENT WARNING

COMPONENTS IDENTIFIED BY MARK A 0R DOTTED
LINE WITH MARK & ON THE SCHEMATIC DIAGRAMS
AND IN THE PARTS LIST ARE CRITICAL TO SAFE
OPERATION. REPLACE THESE COMPONENTS WITH
SONY PARTS WHOSE PART NUMBERS APPEAR AS
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-
LISHED BY SONY.

ATTENTION AUCOMPOISANT AYANT RAPPORT
A LA SECURITE!

LES COMPOSANTS IDENTIFIES PAR UNE MAROUE @
SUR LES DIAGRAMMES SCHEMATIOUES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER crss COM-
POSANTS QUE PAR DES PIECES SONY DONT LES
NUMéRos SONT DONNES DANS cs MANUEL ou
DANS LES SUPPLEMENTS PUBLIES PAR soNv.

DICTATflR/TRANSCRIBER
S O N Y;

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BM-77

TABLE OF CONTENTS

Section Ltle fizgg

1. SERVICING NOTES
Notes for Repairing .............................. 3
LCD Check Method ............................. 3
Microcomputer pPD75308GF-496v339 (1C112) ........ 4

2. GENERAL
Features ......................................... 10
How to Use This Manual . . . .10
Precautions ..................................... 10
Operation Flow Chart ........................... 11
Location and Function of Controls .................. 12
Preparation ...................................... 14
Dictation ...... , ,
Transcription .................................... 19
Erasing ......................................... 2]
Alarm System llllllllllll ........................ 22
Examples of Dictation and transcription ............ 23
Other Convenient Functions ........................ 24

Section Title Page
3. MECHANICAL ADJUSTMENTS .................. 25
4. ELECTRICAL ADJUSTMENTS .................... 26
5. DIAGRAMS

5-1. Semiconductor Lead Layouts .................... 27
5-2. Printed Wiring Boards .......................... 28
5-3. Schematic Diagram .............................. 33
6. EXPLODED VIEWS

6-1. Cabinet Section ................................ 37
6-2, Mechanism Deck Section (1) .................... 38
6-3. Mechanism Deck Section (2) .......... 39
7. ELECTRICAL PARTS LIST ...................... 40

SAFETY CH ECK-OUT

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.

LEAKAGE TEST

The AC leakage from any exposed metal part to

earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must

not exceed 0.5 mA (500 microampets).

Leakage

current can be measured by any one of three
methods.

I.

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

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

Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The limit indication is 0.75 V, 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 3 2V AC range are
suitable. (See Fig. A)

Fig. A.

To Exposed Metal
Part: on Set

rfi

0.75;:F I 1.5kfl

'7 Earth Ground

A C
V0 ltme (el
(0. 75 V)

Using an AC voltmeter to check AC leakage.