SECTION 1
SERVICING NOTES
SAFETY CHECK-OUTNOTES ON HANDLING THE OPTICAL PICK-UP
After correcting the original service problem, perform the folloBLOCK OR BASE UNITw-
ing safety check before releasing the set to the customer:
Check the antenna terminals, metal trim, Ometallized� knobs,The laser diode in the optical pick-up block may suffer electro-
screws, and all other exposed metal parts for ACstatic br leakage.eak-down because of the potential difference generated
Check leakage as described below.by the charged electrostatic load, etc. on clothing and the human
body.
During repair, pay attention to electrostatic break-down and also
LEAKAGE
use the procedure in the printed matter which is included in the
The AC leakage from any exposed metal part to earth ground and
repair parts.
from all exposed metal parts to any exposed metal part having a
The flexible board is easily damaged and should be handled with
return to chassis, must not exceed 0.5 mA (500 microampers.).
care.
Leakage current can be measured by any one of three methods.
1. A commercial leakage tester, such as the Simpson 229 or RCA
NOTES ON LASER DIODE EMISSION CHECK
WT-540A. Follow the manufacturersO instructions to use these
instruments.
The laser beam on this model is concentrated so as to be focused
2. A battery-operated AC milliammeter. The Data Precision 245
on the disc reflective surface by the objective lens in the optical
digital multimeter is suitable for this job.
pick-up block. Therefore, when checking the laser diode emis-
3. Measuring the voltage drop across a resistor by means of a
sion, observe from more than 30 cm away from the objective lens.
VOM or battery-operated AC voltmeter. The Olimit� indica-
tion is 0.75 V, so analog meters must have an accurate low-
LASER DIODE AND FOCUS SEARCH OPERATION
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
CHECK
amples of a passive VOM that is suitable. Nearly all battery
operated digital multimeters that have a 2 V AC range are suit-
Carry out the OS curve check� in �CD section adjustment� and
able. (See Fig. A)
check that the S curve waveform is output repeatedly.
To Exposed Metal
Parts on Set
AC
0.15 ?F1.5 kWvoltmeter
(0.75 V)
Earth Ground
Fig. A. Using an AC voltmeter to check AC leakage.
SAFETY-RELATED COMPONENT WARNING!!ATTENTION AU COMPOSANT AYANT RAPPORT
� LA S?CURIT?!
COMPONENTS IDENTIFIED BY MARK ! OR DOTTED
LINE WITH MARK ! ON THE SCHEMATIC DIAGRAMSLES COMPOSANTS IDENTIFI?S PAR UNE MARQUE !
AND IN THE PARTS LIST ARE CRITICAL TO SAFESUR LES DIAGRAMMES SCH?MATIQUES ET LA LISTE
OPERATION. REPLACE THESE COMPONENTS WITHDES PIéCES SONT CRITIQUES POUR LA S?CURIT?
SONY PARTS WHOSE PART NUMBERS APPEAR ASDE FONCTIONNEMENT. NE REMPLACER CES COM-
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-POSANTS QUE PAR DES PIéCES SONY DONT LES
LISHED BY SONY.NUM?ROS SONT DONN?S DANS CE MANUEL OU
DANS LES SUPPL?MENTS PUBLI?S PAR SONY.
� 3 � |
ACEC
