SECTION 2
SERVICE NOTE
Precautions for Checking Emission of Laser Diode
NOTES ON HANDLING THE OPTICAL PICK-UPLaser light of the equipment is focused by the object lens in the
BLOCK OR BASE UNIToptical 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
The laser diode in the optical pick-up block may suffer electro-
static breakdown because of the potential difference generated byapart from the object lens when you check the emission of laser
the charged electrostatic load, etc. on clothing and the human body.diode.
During repair, pay attention to electrostatic breakdown and also
use the procedure in the printed matter which is included in theLaser Diode Checking Methods
repair parts.During normal operation of the equipment, emission of the laser
The flexible board is easily damaged and should be handled withdiode is prohibited unless the upper panel is closed while turning
care.ON the S801 (push switch type).
The following two checking methods for the laser diode are oper-
able.
NOTES ON LASER DIODE EMISSION CHECK
The laser beam on this model is concentrated so as to be focusedY Method (In the service mode or normal operation):
on the disc reflective surface by the objective lens in the opticalEmission of the laser diode is visually checked.
pick-up block. Therefore, when checking the laser diode emis-1. Open the upper lid.
sion, observe from more than 30 cm away from the objective lens.2. Push the S801 as shown in Fig. 1.
Befor Replacing the Optical Pick-Up Block3. Press the ^ key.
Please be sure to check thoroughly the parameters as par the OOp-4. Check the object lens for confirming normal emission of the
tical Pick-Up Block Checking Procedures� (Part No.: 9-960-027-laser diode. If not emitting, there is a trouble in the automatic
11) issued separately before replacing the optical pick-up block.power control circuit or the optical pick-up.
Note and specifications required to check are given below.During normal operation, the laser diode is turned ON about
2.5 seconds for focus searching.
Y FOK output: IC501 !a pin
When checking FOK, remov the lead wire to disc motor.
Y S curve P-to-P value: 0.6 - 1.8 #� pinVp-p IC501
When checking S curve P-to-P value, remove the lead wire toS801
disc motor.
Y RF signal P-to-P value: 0.8 - 1.2 Vp-p
Y Traverse signal P-to-P value: 1.2 Vp-p
Y The repairing grating holder is impossible.
Fig. 1 Method to push the S801
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ACEC
