SAFETY CHECK-OUT
After correcting the original service problem, perform the following
safety checks before releasing the set to the customer:
1. Check the area of your repair for unsoldered or poorly-sol-LEAKAGE TEST
dered connections. Check the entire board surface fThe Aor solderC leakage from any exposed metal part to earth ground
splashes and bridges.and from all exposed metal parts to any exposed metal part having
a return to chassis, must not exceed 0.5 mA (500 microamperes).2. Check the interboard wiring to ensure that no wires are
Leakage current can be measured by any one of three methods.Opinched� or contact high-wattage resistors.
1. A commercial leakage tester, such as the Simpson 229 or RCA3. Look for unauthorized replacement parts, particularly transis-
WT-540A. Follow the manufacturers' instructions to use these
tors, that were installed during a previous repair. Point them
instruments.out to the customer and recommend their replacement.
2. A battery-operated AC milliammeter. The Data Precision 245
4. Look for parts which, though functioning, show obvious signs
digital multimeter is suitable for this job.of deterioration. Point them out to the customer and recom-
mend their replacement.3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The Olimit� indica-5. Check the B+ voltage to see it is at the values specified.
tion is 0.75V, so analog meters must have an accurate low-
6. Check the B+ voltage to see it is at the values specified.
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-
7. Check the antenna terminals, metal trim, Ometallized� knobs,amples of a passive VOM that is suitable. Nearly all battery
screws, and all other exposed metal parts for operaAC leakagted dige.ital multimeters that have a 2V AC range are suit-
Check leakage as described below.able. (See Fig. A)
To Exposed Metal
Parts on Set
WARNING!!
WHEN SERVICING, DO NOT APPROACH THE LASER
ACEXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS
0.15 ?F1.5 kWVoltmeterNECESSARY TO CONFIRM LASER BEAM EMISSION,
(0.75 V)
BE SURE TO OBSERVE FROM A DISTANCE OF
MORE THAN 25 cm FROM THE SURFACE OF THE
OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.
Earth Ground
CAUTION:
Fig. A Using AC voltmeter to check AC leakage
The use of optical instrument with this product will increase eye
hazard.
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.
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 SAFE SUR 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.
� 2 � |
ACEC
SONY
