Sony STR-K700 Service Manual - Page 3

STR-K700 SAFETY CHECK-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 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" 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 2 V AC range are suitable. (See Fig. A) To Exposed Metal Parts on Set 0.15 µF 1.5 kΩ AC voltmeter (0.75 V) TABLE OF CONTENTS 1. GENERAL 4 2. TEST MODE 10 3. DIAGRAMS 3-1. Block Diagram - MAIN Section 12 3-2. Block Diagram - DISPLAY/POWER Section 13 3-3. Printed Wiring Board - DIGITAL Board (Side A) - ...... 14 3-4. Printed Wiring Board - DIGITAL Board (Side B) - ...... 15 3-5. Schematic Diagram - DIGITAL Board (1/3 16 3-6. Schematic Diagram - DIGITAL Board (2/3 17 3-7. Schematic Diagram - DIGITAL Board (3/3 18 3-8. Printed Wiring Board - MAIN Board 19 3-9. Schematic Diagram - MAIN Board (1/3 20 3-10. Schematic Diagram - MAIN Board (2/3), HEADPHONE Board 21 3-11. Schematic Diagram - MAIN Board (3/3), ADCC Board, STANDBY Board 22 3-12. Printed Wiring Boards - ADCC Board, HEADPHONE Board 23 3-13. Printed Wiring Board - STANDBY Board 24 3-14. Printed Wiring Boards - DISPLAY Board, POWER Board 25 3-15. Schematic Diagram - DISPLAY Board, POWER Board 26 4. EXPLODED VIEWS 4-1. Front Panel Section 34 4-2. Chassis Section 35 5. ELECTRICAL PARTS LIST 36 Earth Ground Fig. A. Using an AC voltmeter to check AC leakage. 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 PUBLISHED BY SONY. ATTENTION AU COMPOSANT AYANT RAPPORT À LA SÉCURITÉ! LES COMPOSANTS IDENTIFIÉS PAR UNE MARQUE 0 SUR LES DIAGRAMMES SCHÉMATIQUES ET LA LISTE DES PIÈCES SONT CRITIQUES POUR LA SÉCURITÉ DE FONCTIONNEMENT. NE REMPLACER CES COM- POSANTS QUE PAR DES PIÈCES SONY DONT LES NUMÉROS SONT DONNÉS DANS CE MANUEL OU DANS LES SUPPLÉMENTS PUBLIÉS PAR SONY. 3