6
SECTION 1
SERVICING NOTES
The laser diode in the optical pick-up block may suffer electro-
static break-down because of the potential difference generated
by the charged electrostatic load, etc. on clothing and the human
body.
During repair, pay attention to electrostatic break-down 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.
For CD
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 emis-
sion, observe from more than 30 cm away from the objective lens.
LASER DIODE AND FOCUS SEARCH OPERATION
CHECK
Carry out the “S curve check” in “CD section adjustment” and
check that the S curve waveforms is output three times.
For MD
NOTES ON LASER DIODE EMISSION CHECK
Never look into the laser diode emission from right above when
checking it for adjustment. It is feared that you will lose your sight.
NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT
Model
Part No.
US model
4-230-771-0
s
Canadian model
4-230-771-1
s
AEP, UK models
4-230-771-2
s
Singapore model
4-230-771-3
s
MODEL IDENTIFICATION
— BACK PANEL —
Part No.
(Figure A)
CLEANING OBJECTIVE LENS OF OPTICAL PICK-UP
• In cleaning the objective lens of optical pick-up, be sure the
following below.
1. In cleaning the lens, do not apply an excessive force.
As the optical pick-up is vulnerable, application of excessive
force could damage the lens holder.
2. In cleaning, do not use a cleaner other than exclusive cleaning
liquid (KK-91 or isopropyl alcohol).
3. Wipe the objective lens spirally from center toward outside.
(See Figure A)
4. Eject the disk, if loaded.
5. Disconnect the power cord from the socket to shut off the power
supply.
6. When cleaning the objective lens of optical pick-up in CD,
refer to “HOLDER (BU) ASS’Y” on page 23.
SERVICE POSITION
Please put the MAIN board straight as the figure shown below
when performing adjustment or check on the MAIN board.
MAIN BOARD
NOTE ON VOLTAGE ADJUSTMENT
Be sure to execute the Voltage Adjustment on page 44, whenever
the CD base unit (BU-21BD53), mounted MAIN board, and IC506,
R550, R551, or RV500 on the MAIN board were replaced.
