Read Sony ST-SA50ES Service Manual online
— 2 —
1. GENERAL
............................................................................ 3
2. DISASSEMBLY
2-1.
Panel, Front Assembly ........................................................ 4
2-2.
Display Board, Encoder Board, AC SW Board .................. 4
2-3.
Panel Front ......................................................................... 4
3. TEST MODE
........................................................................ 5
4. ELECTRICAL ADJUSTMENTS
................................... 7
5. DIAGRAMS
5-1.
Circuit Boards Location ................................................... 11
5-2.
Printed Wiring Board – Display Section – ....................... 13
5-3.
Schematic Diagram – Display Section – .......................... 15
5-4.
Printed Wiring Board – Tuner Section – .......................... 17
5-5.
Schematic Diagram – Tuner Section (1/2)– ..................... 19
5-6.
Schematic Diagram – Tuner Section (2/2)– ..................... 21
5-7.
IC Pin Function ................................................................ 23
5-8.
IC Block Diagrams ........................................................... 24
6. EXPLODED VIEW
6-1.
Front Panel and Case Section ........................................... 25
7. ELECTRICAL PARTS LIST
......................................... 26
TABLE OF CONTENTS
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK
!
OR 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
PUBLISHED BY SONY.
COMPONENTS WITH SONY PARTS WHOSE PART NUMBERS
APPEAR AS SHOWN IN THIS MANUAL OR IN SUPPLEMENTS
PUBLISHED BY SONY.
SAFETY CHECK-OUT
After correcting the original service problem, perform the
following safety checks 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.
following safety checks 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
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 microampers).
Leakage current can be measured by any one of three methods.
from all exposed metal parts to any exposed metal part having a
return to chassis, must not exceed 0.5 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
instruments.
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.
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 0.75 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)
VOM or battery-operated AC voltmeter. 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)
Earth Ground
AC
voltmeter
(0.75V)
voltmeter
(0.75V)
1.5k
Ω
0.15
µ
F
Fig. A. Using an AC voltmeter to check AC leakage.
To Exposed Metal
Parts on Set
Parts on Set
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