Sony hcd eh 12 service manual

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2 HCD-EH12 Notes on chip component replacement -Never reuse a disconnected chip component. -Notice that the minus side of a tantalum capacitor may be damaged by heat. Flexible Circuit Board Repairing -Keep the temperature of the soldering iron around 270 ËšC during repairing. -Do not touch the soldering iron on the same conductor of the circuit board (within 3 times). -Be careful not to apply force on the conductor when soldering or unsoldering. 1. SERVICING NOTES ............................................... 3 2. GENERAL ................................................................... 4 3. DISASSEMBLY 3-1. Disassembly Flow ........................................................... 6 3-2. Rear Cabinet Section ....................................................... 6 3-3. Front Cabinet Section, Top Cabinet Section and MAIN Board .................................................................... 7 3-4. Mechanical Deck (H-21SB) ............................................ 7 3-5. Base Unit Section (BU-K8BD83S-WOD) ...................... 8 3-6. Optical Pick-up Block (KSM-213CDP) .......................... 8 4. TEST MODE .............................................................. 9 5. MECHANICAL ADJUSTMENTS ....................... 10 6. ELECTRICAL ADJUSTMENTS ......................... 10 7. DIAGRAMS 7-1. Block Diagram -“ CD SERVO Section -“ ......................... 14 7-2. Block Diagram -“ TUNER Section -“ ............................... 15 7-3. Block Diagram -“ MAIN Section -“ .................................. 16 7-4. Printed Wiring Board -“ CD Board -“ ............................... 18 7-5. Schematic Diagram -“ CD Board -“ .................................. 19 7-6. Printed Wiring Boards -“ MAIN Section -“ ...................... 20 7-7. Schematic Diagram -“ MAIN Section (1/3) -“ .................. 21 7-8. Schematic Diagram -“ MAIN Section (2/3) -“ .................. 22 7-9. Schematic Diagram -“ MAIN Section (3/3) -“ .................. 23 7-10. Printed Wiring Board -“ PANEL Board -“ ........................ 24 7-11. Schematic Diagram -“ PANEL Board -“ ........................... 25 8. EXPLODED VIEWS 8-1. Overall Section ................................................................ 33 8-2. Front Cabinet Section ...................................................... 34 8-3. Top Cabinet Section ........................................................ 35 8-4. Base Unit Section (BU-K8BD83S-WOD) ...................... 36 9. ELECTRICAL PARTS LIST ................................ 37 CAUTION Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure. 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. TABLE OF CONTENTS 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) 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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3 HCD-EH12 SECTION 1 SERVICING NOTES The laser diode in the optical pick-up block may suffer electrostatic break-down because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body. During repair, pay attention to electrostatic break-down and also use the procedure in the printed matter which is included in the repair parts. The flexible board is easily damaged and should be handled with care. NOTES ON LASER DIODE EMISSION CHECK The laser beam on this model is concentrated so as to be focused on the disc reflective surface by the objective lens in the optical pick- up block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens. UNLEADED SOLDER Boards requiring use of unleaded solder are printed with the lead- free mark (LF) indicating the solder contains no lead. (Caution: Some printed circuit boards may not come printed with the lead free mark due to their particular size) : LEAD FREE MARK Unleaded solder has the following characteristics. - Unleaded solder melts at a temperature about 40 ËšC higher than ordinary solder. Ordinary soldering irons can be used but the iron tip has to be applied to the solder joint for a slightly longer time. Soldering irons using a temperature regulator should be set to about 350 ËšC. Caution: The printed pattern (copper foil) may peel away if the heated tip is applied for too long, so be careful! - Strong viscosity Unleaded solder is more viscou-s (sticky, less prone to flow) than ordinary solder so use caution not to let solder bridges occur such as on IC pins, etc. - Usable with ordinary solder It is best to use only unleaded solder but unleaded solder may also be added to ordinary solder. NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT Fig.1 Method to push the SW750 SW750 LASER DIODE AND FOCUS SEARCH OPERATION CHECK During normal operation of the equipment, emission of the laser diode is prohibited unless the upper lid is closed while turning ON the SW750. (push switch type) The following checking method for the laser diode is operable. - Method Emission of the laser diode is visually checked. 1. Open the upper lid. 2. Push the SW750 as shown in Fig.1. Note: Do not push the detection lever strongly, or it may be bent or damaged. 3. Press the CD u button. 4. Check the object lens for confirming normal emission of the laser diode. If not emitting, there is a trouble in the automatic power control circuit or the optical pick-up. In this operation, the object lens will move up and down 2 times along with inward motion for the focus search.