Sharp VC-A422U, Service Manual

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VC-A422U
VC-H822U
IMPORTANT SERVICE NOTES
WARNING :TO REDUCE THE RISK OF FIRE OR ELEC-
TRIC SHOCK, DO NOT EXPOSE THIS AP-
PLIANCE TO RAIN OR MOISTURE.
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK. DO
NOT REMOVE COVER. NO USER-SERVICEABLE
PARTS INSIDE. REFER SERVICING TO QUALIFIED
SERVICE PERSONNEL.
This symbol warns the user of uninsulated voltage
within the unit that can cause dangerous electric shocks.
This symbol alerts the user that there are important
operating and maintenance instructions in the literature
accompanying this unit.
This symbol mark means fast operating fuse.
For continued protection against risk of fire, replace
only with same type fuse F901 (3.0A, 125V).
CAUTION:
BEFORE RETURNING THE VIDEO CASSETTE
RECORDER
Before returning the video cassette recorder to the user,
perform the following safety checks.
1. Inspect all lead dress to make certain that leads are
not pinched or that hardware is not lodged between
the chassis and other metal parts in the video cassette
recorder.
2. Inspect all protective devices such as non-metallic
control knobs, insulation materials, cabinet backs,
adjustment and compartment covers or shields, isola-
tion resistor/capacitor networks, mechanical insula-
tors etc.
3. To be sure that no shock hazard exists, check for
current in the following manner.
●
Plug the AC line cord directly into a 120 volt AC outlet
(Do not use an isolation transformer for this test).
●
Using two clip leads, connect a 1.5k ohm, 10 watt
resistor paralleled by a 0.15
µ
F capacitor in series with
all exposed metal cabinet parts and a known earth
ground, such as a water pipe or conduit.
●
Use an SSVM or VOM with 1000 ohm per volt, or
higher, sensitivity or measure the AC voltage drop
across the resistor (See Diagram).
●
Move the resistor connection to earth exposed metal
part having a return path to the chassis (antenna,
metal cabinet, screw heads, knobs and control shafts,
SSVM
AC SCALE
1.5k ohms.
10W
CONNECT TO
KNOWN EARTH
GROUND
TO EXPOSED
METAL PARTS
0.15 µF
TEST PROBE
etc.) and measure the AC voltage drop across the
resistor. Reverse the AC plug on the set and repeat
AC voltage measurements for each exposed part.
Any reading of 0.45V rms (this corresponds to 0.3mA
rms AC.) or more is excessive and indicates a poten-
tial shock hazard which must be corrected before
returning the video cassette recorder to the owner.
3.0A 125V