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 for solderThe AC 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 RCA
3. 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-
amples of a passive VOM that is suitable. Nearly all battery6. Check the B+ voltage to see it is at the values specified.
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 AC leakage.able. (See Fig. A)
Check leakage as described below.
Unleaded solder
To Exposed Metal
Parts on SetBoards requiring use of unleaded solder are printed with the lead-
free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with
the lead free mark due to their particular size.)
AC : LEAD FREE MARK
Unleaded solder has the following characteristics.
0.15 ?F1.5 k&voltmeter
(0.75 V)Y Unleaded solder melts at a temperature about 40°C higher than
ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
Earth Groundabout 350°C.
Fig. A. Using an AC voltmeter to check AC leakage.Caution: The printed pattern (copper foil) may peel away if the
heated tip is applied for too long, so be careful!
Y Strong viscosity
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
W ARNING!!also be added to ordinary solder.
WHEN SERVICING, DO NOT APPROACH THE LASER
EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS
CAUTION:
NECESSARY TO CONFIRM LASER BEAM EMISSION,
The use of optical instrument with this product will increase eye
BE SURE TO OBSERVE FROM A DISTANCE OF
hazard.
MORE THAN 25 cm FROM THE SURFACE OF THE
OBJECTIVE LENS ON THE OPTICAL PICK-UP BLOCK.
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!!
COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED
LINE WITH MARK 0 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 PUB-
LISHED BY SONY.
� 2 � |
ACEC
