Sony UP-860 - Page 3

SAFETY CHECK-OUT
(US Model only)
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.
Check the interboard wiring to ensure that no
wires are ‘“‘pinched’’ or contact high-wattage
resistors.
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.
Look for unauthorized replacement parts, par-
ticularly transistors, that were installed during a
previous repair. Point them out to the customer
and recommend their replacement.
Look for parts which, though functioning, show
obvious signs of deterioration. Point them out
to the customer and recommend their replace-
ment.
Check the line cord for cracks and abrasion.
Recommend the replacement of any such line
cord to the customer.
Check the condition of the monopole antenna
(if any).
Make sure the end is not broken off, and has
the plastic cap on it. Point out the danger of
impalement on a broken antenna to the
customer, and recommend the antenna’s
replacement.
To Exposed Metal
Parts on Set
AC
voltmeter
{0.75 V}
= Earth Ground
Using an AC voltmeter to check AC leakage.
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 0.5mA (500 microampers).
current
Leakage
can be measured by any one of three
methods.
I.
A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers’ instructions to use these instru-
ments.
A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
The “limit” indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)
meter.