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 line cord for cracks and abrasion. Recommend the
tion is 0.75V, so analog meters must have an accurate low-
replacement of any such line cord to the customer.
voltage scale. The Simpson 250 and Sanwa SH-63Trd are ex-6. Check the B+ voltage to see it is at the values specified.
amples of a passive VOM that is suitable. Nearly all battery
7. Check the antenna terminals, metal trim, Ometallized� knobs,operated digital multimeters that have a 2V AC range are suit-
screws, and all other exposed metal parts for abAle. (See FC leakage. ig. A)
Check leakage as described below.
Unleaded solder
Boards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
To Exposed Metal(Caution: Some printed circuit boards may not come printed with
Parts on Setthe lead free mark due to their particular size.)
: LEAD FREE MARK
Unleaded solder has the following characteristics.
Y Unleaded solder melts at a temperature about 40°C higher than
ACordinary solder.
0.15 ?F1.5 k&voltmeterOrdinary soldering irons can be used but the iron tip has to be
(0.75 V)
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350°C.
Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
Earth Ground
Y Strong viscosity
Fig. A. Using an AC voltmeter to check AC leakage.Unleaded solder is more viscous (sticky, less prone to flow) than
ordinary solder so use caution not to let solder bridges occur
such as on IC pins, etc.
Y Usable with ordinary solder
It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.
W ARNING!!CAUTION:
WHEN SERVICING, DO NOT APPROACH THE LASERThe use of optical instrument with this product will increase eye
hazard.
EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS
NECESSARY TO CONFIRM LASER BEAM EMISSION,
BE SURE TO OBSERVE FROM A DISTANCE OF
MORE THAN 25 cm FROM THE SURFACE OF THECAUTION
OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous ra-
diation exposure.
ATTENTION AU COMPOSANT AYANT RAPPORT
SAFETY-RELATED COMPONENT WARNING!!� LA S?CURIT?!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTEDLES COMPOSANTS IDENTIFI?S PAR UNE MARQUE 0
LINE WITH MARK 0 ON THE SCHEMATIC DIAGRAMSSUR LES DIAGRAMMES SCH?MATIQUES ET LA LISTE
AND IN THE PARTS LIST ARE CRITICAL TO SAFE DES PIéCES SONT CRITIQUES POUR LA S?CURIT?
OPERATION. REPLACE THESE COMPONENTS WITHDE FONCTIONNEMENT. NE REMPLACER CES COM-
SONY PARTS WHOSE PART NUMBERS APPEAR ASPOSANTS QUE PAR DES PIéCES SONY DONT LES
SHOWN IN THIS MANUAL OR IN SUPPLEMENTS PUB-NUM?ROS SONT DONN?S DANS CE MANUEL OU
LISHED BY SONY.DANS LES SUPPL?MENTS PUBLI?S PAR SONY.
� 2 � |
ACEC
