Sony str de 185 service manual

Page 2

3 TABLE OF CONTENTS 1. GENERAL Main unit ................................................................................. 4 Remote button description ....................................................... 5 2. DISASSEMBLY 2-1. Case ..................................................................................... 6 2-2. Front Panel Section ............................................................. 7 2-3. Back Panel ........................................................................... 7 2-4. Main Board ......................................................................... 8 3. TEST MODE ........................................................................ 9 4. DIAGRAMS 4-1. IC Pin Description ............................................................. 10 4-2. Circuit Boards Location .................................................... 11 4-3. Block Diagram – Main Section –...................................... 12 4-4. Block Diagram – Power Section –.................................... 13 4-5. Printed Wiring Board – Main Section –............................ 14 4-6. Printed Wiring Boards – H/P, Outlet Section –................. 15 4-7. Schematic Diagram – Main Section (1/2) –...................... 16 4-8. Schematic Diagram – Main Section (2/2) –...................... 17 4-9. Schematic Diagram – Display Section –........................... 18 4-10. Printed Wiring Board – Display Section –........................ 19 4-11. Printed Wiring Board – Power SW Section –................... 20 5. EXPLODED VIEWS 5-1. Case Section ...................................................................... 21 5-2. Front Panel Section ........................................................... 22 5-3. Chassis Section ................................................................. 23 6. ELECTRICAL PARTS LIST ......................................... 24 STR-DE185 1.5 k Ω 0.15 µF AC voltmeter (0.75 V) To Exposed Metal Parts on Set Earth Ground Fig. A. Using an AC voltmeter to check AC leakage. 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 2V AC range are suitable. (See Fig. A)