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Sony ST-SE370 - Safety Check-out Procedures; AC Leakage Test

Sony ST-SE370
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2
ST-SE370
TABLE OF CONTENTS
1. GENERAL ................................................................... 3
2. DISASSEMBLY
2-1. Disassembly Flow ........................................................... 4
2-2. Case (407026) ................................................................. 4
2-3. MAIN Board ................................................................... 5
3. TEST MODE.............................................................. 6
4. ELECTRICAL ADJUSTMENTS......................... 8
5. DIAGRAMS
5-1. Note for Printed Wiring Boards and
Schematic Diagrams ....................................................... 9
5-2. Printed Wiring Boards MAIN Section ..................... 10
5-3. Schematic Diagram MAIN Section .......................... 11
5-4. Printed Wiring Boards DISPLAY Section ............... 12
5-5. Schematic Diagram DISPLAY Section .................... 13
5-6. IC Pin Function Description ........................................... 14
6. EXPLODED VIEWS
6-1. Case Section .................................................................... 15
6-2. Front Panel Section ......................................................... 16
6-3. Chassis Section ............................................................... 17
7. ELECTRICAL PARTS LIST ............................... 18
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED
LINE WITH MARK 0 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.
SAFETY CHECK-OUT
After correcting the original service problem, perform the follow-
ing 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 microamperes.).
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 indica-
tion is 0.75 V, so analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are
suitable. (See Fig. A)
Fig. A. Using an AC voltmeter to check AC leakage.
1.5 k
0.15 µF
AC
voltmete
r
(0.75 V)
To Exposed Metal
Parts on Set
Earth Ground
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TEL 13942296513 QQ 376315150 892498299
TEL 13942296513 QQ 376315150 892498299
http://www.xiaoyu163.com
http://www.xiaoyu163.com

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