Read Sharp LC-20B5E (serv.man2) Service Manual online
have special safety-related characteristics.
These characteristics are often not evident from visual
inspection, nor can protection afforded by them be
necessarily increased by using replacement components
rated for higher voltage, wattage, etc.
Replacement parts which have these special safety
characteristics are identified in this manual; electrical
components having such features are identified by "
thoroughly familiar with all safety checks and the servicing guidelines which follow:
For continued protection, replacement parts must be
identical to those used in the original circuit.
The use of a substitute replacement parts which do not
have the same safety characteristics as the factory
recommended replacement parts shown in this service
manual, may create shock, fire or other hazards.
higher, sensitivity or measure the AC voltage drop
across the resistor.
parts having a return to the chassis (antenna, metal
cabinet, screw heads, knobs and control shafts,
escutcheon, etc.) and measure the AC voltage drop
across the resistor.
All checks must be repeated with the AC cord plug
connection reversed. (If necessary, a nonpolarized
adaptor plug must be used only for the purpose of
completing these checks.)
Any reading of 0.75V peak (this corresponds to 0.5
mA. peak AC.) or more is excessive and indicates a
potential shock hazard which must be corrected before
returning the monitor to the owner.
(Fire & Shock Hazard)
the following safety checks:
between the chassis and other metal parts in the
adjustment and compartment covers or shields,
isolation resistor-capacitor networks, mechanical
and connect the DC power cable into the receiver's
DC jack. (Do not use an isolation transformer for this
resistor paralleled by a 0.15µF capacitor in series with
all exposed metal cabinet parts and a known earth
ground, such as electrical conduit or electrical ground
connected to an earth ground.
AGAINST A RISK OF FIRE REPLACE ONLY WITH
SAME TYPE F3701 (2A, 250V), F3702 (1.25A, 250V),
F6700 (1.25A, 250V), F6701 (1.25A, 250V), F6702
(1.25A, 250V), F6703 (1.25A, 250V) AND F6704
(1.25A, 250V) FUSE.
the PWBs and service manuals. The alphabetical character following LF shows the type of lead-free solder.
lead wire solder may cause damage or accident due to cracks.
As the melting point of lead-free solder (Sn-Ag-Cu) is higher than the lead wire solder by 40°C, we recommend
you to use a dedicated soldering bit, if you are not familiar with how to obtain lead-free wire solder or soldering bit,
contact our service station or service branch in your area.
solder by 40°C, and as it has poor solder wettability, you may be apt to keep the soldering bit in contact with the
PWB for extended period of time. However, Since the land may be peeled off or the maximum heat-resistance
temperature of parts may be exceeded, remove the bit from the PWB as soon as you confirm the steady soldering
Lead-free solder contains more tin, and the end of the soldering bit may be easily corroded. Make sure to turn on
and off the power of the bit as required.
If a different type of solder stays on the tip of the soldering bit, it is alloyed with lead-free solder. Clean the bit after
every use of it.
When the tip of the soldering bit is blackened during use, file it with steel wool or fine sandpaper.