Safety Check Out Instructions - Sony SAT-W60 Service Manual

SAT-W60
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-
soldered connections. Check the entire board surface
for solder splashes and bridges.
2. Check the interboard wiring to ensure that no wires are
"pinched" or contact high-wattage resistors.
3. Check that all control knobs, shields, covers, ground
straps, and mounting hardware have been replaced. Be
absolutely certain that you have replaced all the insulators.
4. Look for unauthorized replacement parts, particularly
transistors, that were installed during a previous repair.
Point them out to the customer and recommend their
replacement.
5. Look for parts which, though functioning, show obvious
signs of deterioration. Point them out to the customer
and recommend their replacement.
6. Check the line cords for cracks and abrasion.
Recommend the replacement of any such line cord to
the customer.
7. Check the B+ and HV to see if they are specified values.
Make sure your instruments are accurate; be suspicious
of your HV meter if sets always have low HV.
8. Check the antenna terminals, metal trim, "metallized"
knobs, screws, and all other exposed metal parts for AC
Leakage. Check leakage as described below.
SAFETY CHECK-OUT
Leakage Test
The AC leakage from any exposed metal part to earth ground
and from all exposed metal parts to any exposed metal part
having a return to chassis, must not exceed 0.5 mA (500
microampere). Leakage current can be measured by any one
of three methods.
1. A commercial leakage tester, such as the Simpson 229 or
RCA WT-540A. Follow the manufacturers' instructions to use
these instructions.
2. A battery-operated AC milliammeter. The Data Precision 245
digital multimeter is suitable for this job.
3. Measuring the voltage drop across a resistor by means of a
VOM or battery-operated AC voltmeter. The "limit" indication
is 0.75 V, so analog meters must have an accurate low voltage
scale. The Simpson's 250 and Sanwa SH-63Trd are
examples of passive VOMs that are suitable. Nearly all battery
operated digital multimeters that have a 2V AC range are
suitable. (See Figure A)
0.15 µF
— 2 —
To Exposed Metal
Parts on Set
AC
1.5 k Ω
Voltmeter
(0.75 V)
Earth Ground
Figure A