Sharp LC-32BD5T, Service Manual

Page: 3 / 51

IMPORTANT SAFETY PRECAUTIONS VER 1.0
1-1
1. Before returning an instrument to the customer, always make a safety check of the entire instrument,
including, but not limited to, the following items.
a. Be sure that no built-in protective devices are defective and/or have been defeated during servicing. (1)
Protective shields are provided on this chassis to protect both the technician and the customer. Correctly
replace all missing protective shields, including any removed for servicing convenience. (2) When reinstalling
the chassis and/or other assembly in the cabinet, be sure to put back in place all protective devices, including,
but not limited to, nonmetallic control knobs, insulating paper, adjustment and compartment covers/shields,
and isolation resistor/capacitor networks. Do not operate this instrument or permit it to be operated
without all protective devices correctly installed and functioning.
b. Be sure that there are no cabinet openings through which an adult or child might be able to insert their fingers
and contact a hazardous voltage. Such opening include, but not limited to, (1) excessively wide cabinet
ventilation slots, and (2) an improperly fitted and/or incorrectly secured cabinet back cover.
c. Leakage Current Hot Check
— — — —
With the instrument completely reassembled, plug the AC line cord directly
into a 120V AC outlet. (Do not use an isolation transformer during this test.) Use a leakage current tester or a
metering system that complies with American National Standards Institutes (ANSI) C101.1 Leakage Current
for Appliances and Underwriters Laboratories (UL) 478. With the instrument AC switch first in the ON position
and then in the OFF position, measure from a known earth ground (metal water pipe, conduit, etc.) to all
exposed metal parts of the instrument (antennas, handle bracket, metal cabinet, screw heads, metallic
overlays, control shafts, etc.), especially any exposed metal parts that offer an electrical return path to the
chassis. Any current measured must not exceed 0.7 mini-ampere. Reverse the instrument power cord plug in
the outlet and repeat test. ANY MEASUREMENTS NOT WITHIN THE LIMITS SPECIFIED HEREIN
INDICATE A POTENTIAL SHOCK HAZARD THAT MUST BE ELIMINATED BEFORE RETURNING THE
INSTRUMENT TO THE CUSTOMER.
DEVICE
UNDER
TEST
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
TEST ALL
EXPOSED METAL
SURFACES
LEAKAGE
CURRENT
TESTER
+ -
EARTH
GROUND
3. WIRE CORD
AC Leakage Test
(READING
SHOULD NOT
BE ABOVE
3.5mA)