Akai LCT-4216, Service Manual

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5. When replacing a MAIN PCB in the cabinet,
always be certain that all protective are
installed properly such as control knobs,
adjustment covers or shields, barriers, isolation
resistor networks etc.
6. When servicing is required, observe the original
lead dressing. Extra precaution should be given
to assure correct lead dressing in the high
voltage area.
7. Keep wires away from high voltage or high
tempera ture components.
8. Before returning the set to the customer,
always perform an AC leakage current check
on the exposed metallic parts of the cabinet,
such as antennas, terminals, screwheads,metal
overlay, control shafts, etc., to be sure the set
is safe to operate without danger of electrical
shock. Plug the AC line cord directly to the
AC outlet (do not use a line isolation
transformer during this check). Use an AC
voltmeter having 5K ohms volt sensitivity or
more in the following manner.
Connect a 1.5K ohm 10 watt resistor paralleled
by a 0.15µF AC type capacitor, between a
good earth ground (water pipe, conductor etc.,)
and the exposed metallic parts, one at a time.
Measure the AC voltage across the combination
of the 1.5K ohm resistor and 0.15 uF
capacitor. Reverse the AC plug at the AC
outlet and repeat the AC voltage measurements
for each exposed metallic part.
The measured voltage must not exceed 0.3V
RMS.
This corresponds to 0.5mA AC. Any value
exceeding this limit constitutes a potential
shock hazard and must be corrected
immediately.
The resistance measurement should be done
between accessible exposed metal parts and
power cord plug prongs with the power switch
"ON". The resistance should be more than
6M ohms.
AC VOLTMETER
Good earth ground
such as the water Place this probe
on each exposed
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this
apparatus have special safety-related
characteristics.
These characteristics are offer passed
unnoticed by visual spection and the protection
afforded by them cannot necessarily be obtained
by using replacement components rates for a
higher voltage, wattage, etc.
The replacement parts which have these
special safety characteristics are identified by
marks on the schematic diagram and on the parts
list.
Before replacing any of these components,
read the parts list in this manual carefully. The
use of substitute replacement parts which do not
have the same safety characteristics as specified
in the parts list may create shock, fire, or other
hazards.
9. Must be sure that the ground wire of the AC
inlet is connected with the ground of the
apparatus properly.
metallic part pipe, conductor,
etc.
AC Leakage Current Check