Sony CDP 491 Service Manual

Page 2

CDP-195/295/491

SAFETY-RELATED COMPONENT WARNING

COMPONENTS IDENTIFIED BY MARK A OR DOTTED LINE
WITH MARK & ON THE SCHEMATIC DIAGRAMS AND IN
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR
IN SUPPLEMENTS PUBLISHED EV SONY.

ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITEI

LEs COMPOSANTS IDENTIFIES PAR UNE MARQUE A SUR
LES DIAGRAMMES SCHEMATIOUES ET LA LISTE DES
PIECES SONT CRITIQUES POUR LA SECURITE DE FONC-
TIONNEMENT. NE REMPLACER CES COMPOSANTs OUE PAR
DES PIECES SONY DONT LES NUMEROS SONT OONNES
DANS CE MANUEL Ou DANS LEs SUPPLEMENTS PUBLIES
PAR SONv.

PROTECTION OF EYES FROM LASER BEAM DURING SERVICING

This set employs a laser. Therefore, be sure to follow carefully the
instructions below when servicing.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous
radiation exposure.

NOTES ON HANDUNG THE OPHCAL 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.

1. Laser Diode Properties

' Material: GaAlAs

' Wavelength: 780nm

' Emission Duration: continuous

' Laser Output: maxr44r6uW*

* This output is the value measured at a distance of about

200mm from the Objective lens surface on the Optical Pick-up
Block.

2. During service, do not take the Optical Pick-up Block apart, and
do not adjust the APC circuit. If there is a breakdown in the APC
circuit (including laser diode), replace the entire Optical Pick-
up Block (including APC borad).

TABLE OF CONTENTS
M911 I'M Rage Section Eli Rage
1. GENERAL .............. ............ 4 42. Block Diagram ................................................... 10
Location of Controls .................................................. 4 4-3. Waveforms ................ - 13
4-4 Printing Wiring Boards 14
2. ELECTRICAL BLOCK CHECKING ................. 5 45 Schematic diagram ~ 17
4-6. Semiconductor Lead Layouts. I 21
7, D' ............................................ 22
3. DISASSEMBLY OF BASE UNIT ...................... 7 4 '0 B'°°k grams

5. EXPLODED VIEWS. ........... 24

4. DIAGRAMS ........ ............................................ 8

4-1. Pin Function of lCtO1 and |C401 8

6. ELECTRICAL PARTS LIST ...... 28