Sony bm 88 service manual

Page 1

sr

US Model
Canadian Model
AEP Model

UK Model
E Model

SPECIFICATIONS N EW

MB-88~59

Model Name Using Similar Mechanism
Tape Transport Mechanism Type

Recording syslem rack 2-channel monaural
(L channel lor electronic index signals, n channel lor sound signals)
45 cm/s (17/. in./s), ac cm/s (Ev/i. in./s)
Applox. 2 min. 20 sec. with Sony cassette Dost)
200A5,000 Hz (at 244 CHI/S)
2004.000 Hz (at 4,8 cm/s)
Speaker Approx 5.7 cm (2v. inches) dis.
Powel output 350 mW (al 3% dislonion)
Inpul TELEPHONE PICKUP (mInIIack)
Sensitivity 0.2 mV
input impedance in kchms
EAFIPHONE (minilack)
Ior 8-300-ohm earphones
CONTROL UNIT conneclor
Ior HU-BO or FS-75
9 V DC

Tape speed

Fast winding lime

Frequency response

Outpux

Power requilemenls

Power consumption
Dimensions

Weight
Supplied accessory

DO IN 9 v jack accepts the supplied AC power adaplar Io! use on
120 V Ac, 60 Hz lus. Canadian modeI)
220 V AC, 50 H2 (AEP, E mode
240 V AC, 50 Hz IUK model)
I4 W (Us, Canadian model) (with the SuDDIIed AC power adaptor!
l3 W (AEP, UK, E model) (WIth (he supplled AC power adaptor)
Approx. 200 x 70 x 245 mm (w/h/d) (77/9 x 27. x 9% inches)
Including projecting pans and controls
Approx 1.2 kg (2 lb I1 02)
Ac power adaptor (1)

Design and specIIicaIions subject (a change without notice.

SAFETY-RELATED COMPONENT WARNINGII

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

ATTENTION Au COMPOSANT AVANT RAPPORT
A LA SECURITE!

LES COMPOSANTS IDENTIFIES PAR UNE MARQUE A
SUR LES DIAGRAMMES SCHEMATIOUES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA sécuanE
DE FONCTIONNEMENT. NE REMPLACER CEs COM»
POSANTS QUE PAR DES PIECES SONY DONT LES
NuMERos SONT DONNES DANS CE MANUEL ou
DANS LEs SUPPLEMENTS PUBLlEs PAR SONY.

DICTATflR/TRANSCRIBER
ONY;

Page 2

Section

1.

TABLE OF CONTENTS

nge

Title

SERVICING NOTES
Note for Repairing .
LCD Check Method ................................ 3

Microcomputer ,uPD75308GF-496-3B9 (IC112) ........ 4
GENERAL

Features ......................................... 10
How to Use This Manual .............

Precautions .......... . .
Operation Flow Chart ............................ 11
Location and Function of Controls .................. 12
Preparation ...................................... 14
Dictation .......................................... 15
Transcription

Erasing ........

Alarm System .................................... 22
Examples of Dictation and transcription ............ 23
Other Convenient Functions ........................ 24

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

5-1i Semiconductor Lead Layouts .................... 30
5-2. Printed Wiring Boards .......................... 32
5-3. Schematic Diagram .............................. 37
6. EXPLODED VIEWS

6-1. Cabinet Section .............................. 41
6-2. Mechanism Deck Section (1) .................... 42
643. Mechanism Deck Section (2) .................... 43
7. ELECTRICAL PARTS LIST ...................... 44

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 05 mA (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 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
mUItimeters that have a 2V AC range are
suitable. (See Fig. A)

Fig. A.

To Exposed Metal
Parts on Set

_-|

1.5m /
'__I

." Earth Ground

A C
voltmeter
(0.75 W

0.15uF i-
L

IL

Using an AC voltmeter to check AC leakage.