Servicing Notes - Sony D-E990 Service Manual

NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
The laser diode in the optical pick-up block may suffer electro-
static 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 "Op-
tical Pick-Up Block Checking Procedures" (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: 0.35 to 0.55 Vp-p
SECTION 1

SERVICING NOTES

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 lid is closed while turning ON
the S801. (push switch type)
The following two checking methods for the laser diode are oper-
able.
• 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 hav-
ing a thin tip as shown in Fig.1.
3. Press the
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 pickup is faulty.
In this operation, the objective lens will move up and down 5
times along with inward motion for the focus search.
S801
– 3 –
button.
u
detection lever
detection lever
MAIN board
Fig. 1 Method to push the S801