Table Of Contents - Sony MEGA BASS CFS-720 Service Manual

CFS-720
TABLE OF CONTENTS
Section Title Page Section Title Page
1. GENERAL 5-2. Printed Wiring Boards ............... cess eee a
1-1. Location and Function of Controls .............. 3 5-3. Schematic Diagram -Tuner Section-.......... 15
5-4. Schematic Diagrams -Audio Section- ........ 19
2. DISASSEMBLY .
2-1. Removal of Cassette Lid Assy ......0...eeeee eee 4 6. EXPLODED VIEWS
| 6-1. Cabinet (Rear), Speaker Section ................ 22
3. MECHANICAL ADJUSTMENTS.................... 5 6-2. Cabinet (Front) Section ...........0.e cece eens 23
6-3. Deck A mechanism Section (1) ................ 24
4. ELECTRICAL ADJUSTMENTS 6-4. Deck A mechanism Section (2) ................ 25
4-1. Tape Recorder Section ............ 0... cece eee 6 6-5. Deck A mechanism Section (3) ................ 26
B20: « ~ RACIO SECLION paket Praia d wendlen de sewed 8 6-6. Deck B mechanism Section (1) ................ 27
6-7. Deck B mechanism Section (2) ..............7. 28
5. DIAGRAMS
5-1. Semiconductor Lead Layouts ...............0 10 7. ELECTRICAL PARTS LIST ...................... 29
SAFETY CHECK-OUT
After correcting the original service problem, 3. 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 a 2V AC range are
suitable. (See Fig. A)
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 meta! part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5mA (500 microampers). Leakage
current can be measured by any one of three
methods.
To Exposed Metal
Parts on Set
1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A._ Follow the
manufacturers' instructions to use these instru-
ments.
AC
voltmeter
ee (0.75 V)
2. A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
Earth Ground
Fig. A. Using an AC voltmeter to check AC leakage.
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK A OR DOTTED
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LINE WITH MARK A 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.
LES COMPOSANTS IDENTIFIES PAR UNE MARQUE /\
SUR LES DIAGRAMMES SCHEMATIQUES ET LA LISTE
DES PIECES SONT CRITIQUES POUR LA SECURITE
DE FONCTIONNEMENT. NE REMPLACER CES COM-
POSANTS QUE PAR DES PIECES SONY DONT LES
NUMEROS SONT DONNES DANS CE MANUEL OU
DANS LES SUPPLEMENTS PUBLIES PAR SONY.