SECTION 1
SERVICING NOTE
SAFETY CHECK-OUT
NOTES ON HANDLING THE OPTICAL PICK-UP BLOCK
After correcting the original service problem, perform the follow-OR BASE UNIT
ing safety checks before releasing the set to the customer:
Check the antenna terminals, metal trim, Ometallized� knobs, screws,The laser diode in the optical pick-up block may suffer electrostatic
and all other exposed metal parts for AC leakage. Checbreakdok leakagwn because of the potential dife asference generated by the
described below.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
LEAKAGE
parts.
The AC leakage from any exposed metal part to earth Ground and
The flexible board is easily damaged and should be handled with
from all exposed metal parts to any exposed metal part having a
care.
return to chassis, must not exceed 0.5 mA (500 microampers). Leak-
age current can be measured by any one of three methods.
NOTES ON LASER DIODE EMISSION CHECK
1. A commercial leakage tester, such as the Simpson 229 or RCA
WT-540A. Follow the manufacturersO instructions to use these
The laser beam on this model is concentrated so as to be focused on
instruments.
the disc reflective surface by the objective lens in the optical pick-
2. A battery-operated AC milliammeter. The Data Precision 245
up block. Therefore, when checking the laser diode emission, ob-
digital multimeter is suitable for this job.
serve from more than 30 cm away from the objective lens.
3. Measuring the voltage drop across a resistor by means of a VOM
or battery-operated AC voltmeter. The Olimit� indication is 0.75
LASER DIODE AND FOCUS SEARCH OPERATION
V, so analog meters must have an accurate low-voltage scale.
CHECK
The Simpson 250 and Sanwa SH-63Trd are examples of a pas-
sive VOM that is suitable. Nearly all battery operated digital
Carry out the OS curve check� in OCD section adjustment� and check
multimeters that have a 2V AC range are suitable. (See Fig. A)
that the S curve waveform is output repeatedly.
To Exposed Metal
Parts on Set
AC
0.15mF1.5kWvoltmeter
(0.75V)
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 LINELES COMPOSANTS IDENTIFI?S PAR UNE MARQUE ! SUR
WITH MARK ! ON THE SCHEMATIC DIAGRAMS AND INLES DIAGRAMMES SCH?MATIQUES ET LA LISTE DES
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.PIéCES SONT CRITIQUES POUR LA S?CURIT? DE
REPLACE THESE COMPONENTS WITH SONY PARTSFONCTIONNEMENT. NE REMPLACER CES COMPOSANTS
WHOSE PART NUMBERS APPEAR AS SHOWN IN THISQUE PAR DES PIéCES SONY DONT LES NUM?ROS
MANUAL OR IN SUPPLEMENTS PUBLISHED BY SONY.SONT DONN?S DANS CE MANUEL OU DANS LES
SUPPL?MENTS PUBLI?S PAR SONY.
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ACEC
