Haier NS-13CTV, Руководство по обслуживанию

Страница: 3 / 15

.
1. SAFETY PRECAUTIONS
1. The design of this product contains special hardware, m any
circuits and components especially for safety purposes. For
continued prot ection, no changes should be made to the
original design unless authorized in writing by the
manufacturer. Replacem ent parts m ust be identical to those
used in the original circuits. Service should be performed by
qualified personnel only.
2.
Alterations of the design or circuitry of the products should
not be made. Any design alterations or additions will void the
manufacturer’s warranty and will further relieve the
manufacturer of responsibility for personal injury or property
damage resulting therefrom.
9. Isolation Check
(Safety for Electrical Shock Hazard)
After re-assem bling the product, always perform an isolation
check on the exposed metal parts of the cabinet (ant enna
term inals, video/ audio input and output terminals, Control
knobs, metal cabinet, screw heads, earphone jack, control
shafts, etc.) to be sure the product is safe to operate without
danger of electrical shock.
10. The surface of the TV screen is coated with a thin film which
can easily be damaged. Be very careful with it when handle
the TV. Should the TV screen becom e soiled, wipe it with a
soft dry cloth. Never rub it forcefully. Never use any cleaner
or detergent on it.
3. Many electrical and m echanical parts in the products have
special safety-related characteristics. These characteristics
are oft en not evident from visual inspection nor can the
protection afforded by them necessarily be obtained by using
replacem ent components rated for higher voltage, wattage,
etc. Replacem ent parts which have these special safety
characteristics are identified in the parts list of Service
manual. Electrical com ponents having such features are
identified by shading on the schem atics and by (
) on
the parts list in Service manual. The use of a substitut e
replacem ent which does not have the sam e safety
characteristics as the recommended replacem ent part
shown in the parts list of Service manual may cause shock,
fire, or other hazards
4.
Don’t short between the LIVE side ground and
ISOLATED (NEUTRAL) side ground or EARTH side
ground when repairing. Some model’s power circuit is
partly different in the GND. The difference of the GND is
shown by the LIVE: (
) side GND, ISOLATED
(NEUTRAL): ( ) side GND and EARTH: ( ) side GND.
Don’t short between the LIVE side GND and ISOLATED
(NEUTRAL) side GND or EARTH side GND and never
measure with a m easuring apparat us (oscilloscope etc.) the
LIVE side GND and ISOLATED (NEUTRAL) side GND or
EARTH side GND at the sam e tim e. If above note will not be
kept, a fuse or any parts will be broken.
5.
If any repair has been m ade to the chassis, it is
recomm ended that the B1 setting should be checked or
adjusted (See ADJUSTMENT OF B1 POW ER SUPPLY).
6.
The high voltage applied to the picture tube must conform to
that specified in Service manual. Excessive high voltage can
cause an increase in X-Ray em ission, arcing and possible
component dam age, therefore operation under excessive
high voltage conditions should be kept to a minim um, or
should be prevented. If severe arcing occurs, rem ove the A C
power immediately and determine the cause by visual
inspection (incorrect installation, cracked or m elt ed high
voltage harness, poor soldering, etc.). To maintain the proper
minimum level of soft X-Ray emission, com ponents in the
high voltage circuitry including the picture tube must be the
exact replacem ents or alternatives approved by the
manufacturer of the complete product.
(1) Dielectric Strength Test
The isolation between the AC prim ary circuit and all metal
parts exposed to the user, particularly any exposed metal
part having a return path to the chassis should withstand a
voltage of 3000V AC (r.m.s.) for a period of one second.
(…W ithstand a voltage of 1100V AC (r.m.s.) to an applianc e
rated up to 120V, and 3000V AC (r.m.s.) to an applianc e
rated 200V or more, for a period of one second.)
This method of test requires test equipm ent not generally
found in the service trade.
(2) Leakage Current Check
Plug the AC line cord directly int o the AC outlet (do not use
line isolation transform ers during this check). Using a
“Leakage Current Test er”, m easure the leakage current from
each exposed metal part of the cabinet, particularly any
exposed m etal part having a return path t o the chassis, to a
known good earth ground (water pipe, etc.). Any leakage
current must not exceed 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).
● Alternate Check Method
Plug the AC line cord directly into the AC outlet ( do not use
a line isolation transformer during this check.). Use an A C
voltmeter having 1000 ohm s per volt or more sensitivity in
the following manner. Connect a 1500
Ω 10W resistor
paralleled by a 0.15 µ F AC-type capacit or between an
exposed m etal part and a known good earth ground (water
pipe, etc.). Measure the AC voltage across the resistor with
the AC voltmeter. Move the resistor connection to each
exposed metal part, particularly any exposed metal part
having a return path to the chassis, and m easure the AC
voltage across the resistor. Now, reverse the plug in the A C
outlet and repeat each m easurem ent. Any voltage measured
must not exceed 0.75V AC (r.m.s.). This corresponds to
0.5mA AC (r.m .s.).
However, in tropical area, this must not exceed 0.3V AC
(r.m.s.).
This corresponds to 0.2m A AC (r.m.s.)
7. Do not check high voltage by drawing an arc. Use a high
voltage met er or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground fram e
and connecting the other end of the lead through a 10k
Ω 2W
resistor to the anode button.
8. When service is required, observe the original lead dress.
Extra precaution should be given t o assure correct lead
dress in the high voltage circuit area. W here a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the
manufacturer’s replacement components.
3