Sony hcd nez 31 service manual

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3 HCD-NEZ31 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 S820. (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 S820 as shown in Fig.1. Note:Do not push the detection lever strongly, or it may be bent or damaged. 3. Press the 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. 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 HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT SECTION 1 SERVICING NOTES 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 ˚C 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 ˚C. 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. Fig.1 Method to push the S820 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. S820