Servicing Notes - Sony Walkman D-E777 Service Manual

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 30cm away from the objective lens.
Before Replacing the Optical pick-up Block
Please be sure to check thoroughly the parameters as per the "Optical
pick-up Block Checking Procedure" (Part No. : 9-960-027-11) issued
separately before replacing the optical Pick-up block.
Note and specifications required to check are given below.
• FOK output : IC601 eg pin
When checking FOK, remove the lead wire to disc motor.
• RF signal P-to-P value : 0.45 to 0.65Vp-p (D-E777/EJ725)
: 0.38 to 0.6Vp-p (D-EJ721)
SECTION 1

SERVICING NOTES

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 checking method for the laser diode are operable.
Method :
Emission of the laser diode is visually checked.
1. Open the upper lid.
2. Push the S801 as shown in Fig. 1.
3. 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.
D-E777/EJ721/EJ725
S801
Fig.1 Method to push S801
3