SONY DE771
Manual de Servicio

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 breakdown because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body. During repair, pay attention to electrostatic breakdown 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. Befor Replacing the Optical Pick-Up Block Please be sure to check thoroughly the parameters as par the �Optical Pick-Up Block Checking Procedures� (Part No.: 9-960-02711) issued separately before replacing the optical pick-up block. Note and specifications required to check are given below. � FOK output: IC501 !� pin When checking FOK, remove the lead wire to disc motor. � S curve P-to-P value: 0.6 to 1.8 Vp-p IC501 #¡ pin When checking S curve P-to-P value, remove the lead wire to disc motor. � RF signal P-to-P value: 0.8 to 1.2 Vp-p � Traverse signal P-to-P value: 1.2 Vp-p � The repairing grating holder is impossible. Precautions for Checking Emission of Laser Diode Laser light of the equipment is focused by the object lens in the optical pick-up so that the light focuses on the reflection surface of the disc. Therefore, be sure to keep your eyes more then 30 cm apart from the object lens when you check the emission of laser diode. Laser Diode Checking Methods During normal operation of the equipment, emission of the laser diode is prohibited unless the upper panel is closed while turning ON the S801. (push switch type) The following two checking methods for the laser diode are operable. � Method (In the service mode or normal operation): Emission of the laser diode is visually checked. 1. Open the upper lid. 2. Push the S801 as shown in Fig. 1. 3. Press the ^ key. 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. During normal operation, the laser diode is turned ON about 2.5 seconds for focus searching.

S801

Fig. 1 Method to push the S801

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