Zenith D52WLCD Series, Руководство по обслуживанию

Страница: 2 / 71

D52WLCD SAFETY
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS
i
IMPORTANT SAFETY NOTICE
This manual was prepared for use only by properly trained audio-video service
technicians.
When servicing this product, under no circumstances should the original
design be modified or altered without permission from Zenith Electronics
Corporation. All components should be replaced only with types identical to
those in the original circuit and their physical location, wiring and lead dress
must conform to original layout upon completion of repairs.
Special components are also used to prevent shock and fire hazard. These
components are indicated by the letter “x” included in their component
designators and are required to maintain safe performance. No deviations are
allowed without prior approval by Zenith Electronics Corporation.
Circuit diagrams may occasionally differ from the actual circuit used. This way,
implementation of the latest safety and performance improvement changes into
the set is not delayed until the new service literature is printed.
CAUTION: Do not attempt to modify this product in any way. Never perform
customized installations without manufacturer’s approval. Unauthorized
modifications will not only void the warranty, but may lead to property damage
or user injury.
Service work should be performed only after you are thoroughly familiar with
these safety checks and servicing guidelines.
GRAPHIC SYMBOLS
The exclamation point within an equilateral triangle is intended
to alert the service personnel to important safety information in
the service literature.
The lightning flash with arrowhead symbol within an equilateral
triangle is intended to alert the service personnel to the presence
of noninsulated “dangerous voltage” that may be of sufficient
magnitude to constitute a risk of electric shock.
The pictorial representation of a fuse and its rating within an
equilateral triangle is intended to convey to the service personnel
the following fuse replacement caution notice:
CAUTION: FOR CONTINUED PROTECTION AGAINST RISK OF FIRE,
REPLACE ALL FUSES WITH THE SAME TYPE AND RATING AS MARKED
NEAR EACH FUSE.
SERVICE INFORMATION
While servicing, use an isolation transformer for protection from AC line shock.
After the original service problem has been corrected, make a check of the
following:
FIRE AND SHOCK HAZARD
1. Be sure that all components are positioned to avoid a possibility of
adjacent component shorts. This is especially important on items trans-
ported to and from the repair shop.
2. Verify that all protective devices such as insulators, barriers, covers,
shields, strain reliefs, power supply cords, and other hardware have been
reinstalled per the original design. Be sure that the safety purpose of the
polarized line plug has not been defeated.
3. Soldering must be inspected to discover possible cold solder joints, solder
splashes, or sharp solder points. Be certain to remove all loose foreign
particles.
4. Check for physical evidence of damage or deterioration to parts and compo-
nents, for frayed leads or damaged insulation (including the AC cord), and
replace if necessary.
5. No lead or component should touch a high current device or a resistor
rated at 1 watt or more. Lead tension around protruding metal surfaces
must be avoided.
6. After reassembly of the set, always perform an AC leakage test on all exposed
metallic parts of the cabinet (the channel selector knobs, antenna terminals,
handle and screws) to be sure that set is safe to operate without danger of
electrical shock. DO NOT USE A LINE ISOLATION TRANSFORMER DURING THIS
TEST. Use an AC voltmeter having 5000 ohms per volt or more sensitivity in
the following manner: Connect a 1500 ohm, 10 watt resistor, paralleled by
a .15 mfd 150V AC type capacitor between a known good earth ground
water pipe, conduit, etc.) and the exposed metallic parts, one at a time.
Measure the AC voltage across the combination of 1500 ohm resistor and
.15 mfd capacitor. Reverse the AC plug by using a non-polarized adaptor
and repeat AC voltage measurements for each exposed metallic part. Voltage
measured must not exceed 0.75 volts RMS. This corresponds to 0.5 milliamp
AC. Any value exceeding this limit constitutes a potential shock hazard and
must be corrected immediately.
TIPS ON PROPER INSTALLATION
1. Never install any receiver in a closed-in recess, cubbyhole, or closely
fitting shelf space over, or close to, a heat duct, or in the path of heated
air flow.
2. Avoid conditions of high humidity such as: outdoor patio installations
where dew is a factor, near steam radiators where steam leakage is a factor,
etc.
3. Avoid placement where draperies may obstruct venting. The customer
should also avoid the use of decorative scarves or other coverings that
might obstruct ventilation.
4. Wall- and shelf-mounted installations using a commercial mounting kit
must follow the factory-approved mounting instructions. A product mounted
to a shelf or platform must retain its original feet (or the equivalent
thickness in spacers) to provide adequate air flow across the bottom. Bolts
or screws used for fasteners must not touch any parts or wiring. Perform
leakage tests on customized installations.
5. Caution customers against mounting a product on a sloping shelf or in a
tilted position, unless the receiver is properly secured.
6. A product on a roll-about cart should be stable in its mounting to the cart.
Caution the customer on the hazards of trying to roll a cart with small
casters across thresholds or deep pile carpets.
7. Caution customers against using a cart or stand that has not been listed
by Underwriters Laboratories, Inc. for use with its specific model of
television receiver or generically approved for use with TVs of the same or
larger screen size.
8. Caution customers against using extension cords. Explain that a forest of
extensions, sprouting from a single outlet, can lead to disastrous
consequences to home and family.
REGULATORY INFORMATION
This equipment has been tested and found to comply with the limits for a Class
B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful interference when the equip-
ment is operated in a residential installation. This equipment generates, uses
and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur
in a particular installation. If this equipment does cause harmful interference to
radio or television reception, which can be determined by turning the equip-
ment off and on, the user is encouraged to try to correct the interference by one
or more of the following measures: Reorient or relocate the receiving antenna;
Increase the separation between the equipment and receiver; Connect the equip-
ment into an outlet on a circuit different from that to which the receiver is
connected; Consult the dealer or an experienced radio/TV technician for help.
The responsible party for this device’s compliance is:
Zenith Electronics Corporation
201 James Record Road
Huntsville, AL 35824, USA
Digital TV Hotline: 1-800-243-0000