Sony saf 21 service manual
This is the 24 pages manual for sony saf 21 service manual.
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Extracted text from sony saf 21 service manual (Ocr-read)
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– 2 – WARNING!! WHEN SERVICING, DO NOT APPROACH THE LASER EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS NECESSARY TO CONFIRM LASER BEAM EMISSION, BE SURE TO OBSERVE FROM A DISTANCE OF MORE THAN 25 cm FROM THE SURFACE OF THE OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK. 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. 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. Fig. A. Using an AC voltmeter to check AC leakage. 1.5 k Ω 0.15 µF AC voltmeter (0.75 V) To Exposed Metal Parts on Set Earth Ground 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 0.75V, 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 2V AC range are suit- able. (See Fig. A) 1. Check the area of your repair for unsoldered or poorly-sol- dered connections. Check the entire board surface for solder splashes and bridges. 2. Check the interboard wiring to ensure that no wires are pinched or contact high-wattage resistors. 3. Look for unauthorized replacement parts, particularly transis- tors, that were installed during a previous repair. Point them out to the customer and recommend their replacement. 4. Look for parts which, though functioning, show obvious signs of deterioration. Point them out to the customer and recom- mend their replacement. 5. Check the line cord for cracks and abrasion. Recommend the replacement of any such line cord to the customer. 6. Check the B+ voltage to see it is at the values specified. 7. Check the antenna terminals, metal trim, metallized knobs, screws, and all other exposed metal parts for AC leakage. Check leakage as described below. SAFETY CHECK-OUT After correcting the original service problem, perform the following safety checks before releasing the set to the customer:
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– 3 – 1. GENERAL ............................................................ 1-1 2. BLOCK DIAGRAMS 2-1. Overall Block Diagram.................................................. 2-1 2-2. Audio/control Block Diagram ........................................ 2-3 2-3. Power Block Diagram.................................................... 2-5 3. PRINTED WIRING BOARDS AND SCHEMATIC DIAGRAMS 3-1. Circuit Boards Location................................................. 3-2 3-2. Frame Schematic Diagram........................................... 3-3 3-3. Printed Wiring Boards and Schematic Diagrams......... 3-5 Main, Jack, Sub Transformer Printed Wiring Boards ................................................... 3-5 Main, Jack, Sub Transformer Schematic Diagram ....................................................... 3-7 Control Printed Wiring Board ........................................ 3-9 Control Schematic Diagram ..........................................3-11 Power, Speaker Terminal Printed Wiring Boards ..........3-14 Power, Speaker Terminal Schematic Diagram ..............3-15 4. REPAIR PARTS LIST 4-1. Exploded Views............................................................. 4-1 4-1-1. SA-WMS21............................................................... 4-1 4-1-2. SS-MS21.................................................................. 4-2 4-2. Electrical Parts List........................................................ 4-3 TABLE OF CONTENTS Section Title Page