SONY DNF431
Manual de Servicio

D-NF430/NF431 SECTION 1 SERVICING NOTES
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK OR BASE UNIT 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 pickup 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 leadfree 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. OPERATION CHECK WHEN THE LID IS OPEN In performing the repair with the power supplied to the set, removing the MAIN board causes the set to be disabled. In such a case, make a solder bridge to short SL805 (OPEN) on the MAIN board in advance. 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 S801. (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. With a disc not set, turn on the S801 with a screwdriver having a thin tip as shown in Fig.1. 3. Press the u button. 4. Observing the objective lens, check that the laser diode emits light. When the laser diode does not emit light, automatic power control circuit or optical pick-up is faulty. In this operation, the objective lens will move up and down 2 times along with inward motion for the focus search.
lever (detector)

lever (detector) S801

MAIN board

Fig. 1 Method to push the S801
NOTE ON REPLACEMENT OF MAIN BOARD OR EEPROM (IC802) When MAIN board is replaced or EEPROM (IC802) on the MAIN board is replaced, patch processing is needed. Confirm about information of patch processing to each service headquarters.

� MAIN Board (Component Side) �

SL805 (OPEN)

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