SONY DV7000
Instrukcja Serwisowa

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. 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. Before 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: IC601 (£ pin (FOK) When checking FOK, remove the lead wire to disc motor. � S curve P-to-P value: 0.6-1.8 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: 0.8-1.2 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 than 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 lid is closed while turning ON the S401 (push switch type). The following two checking methods for the laser diode are operable. � Method-1 (In the service mode or normal operation): Emission of the laser diode is visually checked. 1. Open the upper lid. 2. Push the S401 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.
S401
digital voltmeter TP (IOP +) TP (IOP �)

� Method-2 (In the service mode or normal operation): Check the value of current flowing in the laser diode. 1. Remove the upper cabinet. 2. Read the current printed on the rear side of the optical pickup. (Print on the rear side of the optical pick-up)

AC2211397
current value A: less than 48 mA

3. Connect a digital voltmeter as shown in Fig. 2. 4. Press the ^ key. 5. Calculate the current value by the reading of the digital voltmeter. Reading of the digital voltmeter (V) ÷ 4.7 (�) = current value (A) (Example) Reading of the digital voltmeter of 0.2256 V: 0.2256 V ÷ 4.7 � = 0.048 (A) = 48 mA 6. Check that the current value is within the following range. � Current value of the label +5 mA (25�C) �11 Variation by temperature: 0.4 mA/�C Current increases with temperature increased. Current decreases with temperature decreased. If the current is more than the range above, there is a trouble in the automatic power control circuit or the laser diode is in deterioration. If less than the range, a trouble exists in the automatic power control circuit or the optical pick-up. � MAIN Board � (Side B)

IC601

Q501 IC501 IC502

+ �

Fig. 1 Method to push the S401

�3�

Fig. 2 Digital voltmeter connecting location