Service Manuals, User Guides, Schematic Diagrams or docs for : ZENITH Proj TV R56W28 ZP28 chassis zenith_zp26-28-rear

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                                                                                               Model Series:
       Product Type:    Digital Rear Projection                                                  R50V26
       Chassis:         ZP26/28                                                                  R56W28
       Manual Series:   PV154                                                                    R60V26
       Manual Part #:   923-03506                                                                R65W28
       Model Line:      E
       Product Year:    2002

                          General Info ................................................. 1
                          Service Menu ................................................ 2
                          Servicing ..................................................... 3
                          Part List ...................................................... 4
                          Diagrams / PCB Layouts .................................. 5
                          Schematics ................................................... 6

                                    Published August 2002
                                   by Technical Publications
                                 Zenith Electronics Corporation
                                    201 James Record Road
                                Huntsville, Alabama 35824-1513

                            Copyright      2002 by Zenith Electronics Corporation

Printed in U.S.A.
This manual was prepared for use only by properly trained audio-video service                                             A.C. Voltmeter
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 x-radiation, shock and fire hazard.
These components are indicated by the letter "x" included in their component                                                   0.15uF
                                                                                                                                                    Place this probe
                                                                                             Good Earth Ground
designators and are required to maintain safe performance. No deviations are                                                                        on each exposed
                                                                                             such as the Water
allowed without prior approval by Zenith Electronics Corporation.                                                            1500 OHM               metal part.
                                                                                             Pipe, Conduit, etc.
Circuit diagrams may occasionally differ from the actual circuit used. This way,
implementation of the latest safety and performance improvement changes into                                                  10 WATT
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                X-RADIATION
customized installations without manufacturer's approval. Unauthorized                  1.    Be sure procedures and instructions to all service personnel cover the
modifications will not only void the warranty, but may lead to property damage                subject of x-radiation. The only potential source of x-rays in current TV
or user injury.                                                                               receivers is the picture tube. However, this tube does not emit x-rays when
                                                                                              the HV is at the factory-specified level. The proper value is given in the
Service work should be performed only after you are thoroughly familiar with
                                                                                              applicable schematic. Operation at higher voltages may cause a failure of
these safety checks and servicing guidelines.
                                                                                              the picture tube or high-voltage supply and, under certain circumstances
                                                                                              may produce radiation in excess of desirable levels.
                                                                                        2.    Only factory-specified CRT anode connectors must be used.
              The exclamation point within an equilateral triangle is intended
              to alert the service personnel to important safety information in         3.    It is essential that the service personnel have available an accurate and
              the service literature.                                                         reliable high-voltage meter.

              The lightning flash with arrowhead symbol within an equilateral           4.    When the high-voltage circuitry is operating properly, there is no possibility
              triangle is intended to alert the service personnel to the presence             of an x-radiation problem. Every time a chassis is serviced, the brightness
              of noninsulated "dangerous voltage" that may be of sufficient                   should be run up and down while monitoring the high voltage with a
              magnitude to constitute a risk of electric shock.                               meter, to be certain that the high voltage does not exceed the specified
                                                                                              value and that it is regulating correctly.
              The pictorial representation of a fuse and its rating within an
                                                                                        5.    When troubleshooting and making test measurements in a product with a
              equilateral triangle is intended to convey to the service personnel
                                                                                              problem of excessively high voltage, avoid being unnecessarily close to
              the following fuse replacement caution notice:
                                                                                              the picture tube and the high voltage power supply. Do not operate the
                                                                                              product longer than necessary to locate the cause of excessive voltage.
              NEAR EACH FUSE.                                                           6.    Refer to HV, B+, and shutdown adjustment procedures described in the
                                                                                              appropriate schematics and diagrams (where used).
While servicing, use an isolation transformer for protection from AC line shock.        IMPLOSION
After the original service problem has been corrected, make a check of the              1.    All direct view picture tubes are equipped with an integral implosion
following:                                                                                    protection system; take care to avoid damage during installation.
                                                                                        2.     Use only the recommended factory replacement tubes.
1. Be sure that all components are positioned to avoid a possibility of                 TIPS ON PROPER INSTALLATION
   adjacent component shorts. This is especially important on items trans-              1.    Never install any receiver in a closed-in recess, cubbyhole, or closely
   ported to and from the repair shop.                                                        fitting shelf space over, or close to, a heat duct, or in the path of heated
2. Verify that all protective devices such as insulators, barriers, covers,                   air flow.
   shields, strain reliefs, power supply cords, and other hardware have been            2.    Avoid conditions of high humidity such as: outdoor patio installations
   reinstalled per the original design. Be sure that the safety purpose of the                where dew is a factor, near steam radiators where steam leakage is a factor,
   polarized line plug has not been defeated.                                                 etc.
3. Soldering must be inspected to discover possible cold solder joints, solder          3.    Avoid placement where draperies may obstruct venting. The customer
   splashes, or sharp solder points. Be certain to remove all loose foreign                   should also avoid the use of decorative scarves or other coverings that
   particles.                                                                                 might obstruct ventilation.
4. Check for physical evidence of damage or deterioration to parts and compo-           4.    Wall- and shelf-mounted installations using a commercial mounting kit
   nents, for frayed leads or damaged insulation (including the AC cord), and                 must follow the factory-approved mounting instructions. A product mounted
   replace if necessary.                                                                      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
5. No lead or component should touch a high current device or a resistor                      or screws used for fasteners must not touch any parts or wiring. Perform
   rated at 1 watt or more. Lead tension around protruding metal surfaces                     leakage tests on customized installations.
   must be avoided.
                                                                                        5.    Caution customers against mounting a product on a sloping shelf or in a
6. After reassembly of the set, always perform an AC leakage test on all exposed              tilted position, unless the receiver is properly secured.
   metallic parts of the cabinet (the channel selector knobs, antenna terminals,
                                                                                        6.    A product on a roll-about cart should be stable in its mounting to the cart.
   handle and screws) to be sure that set is safe to operate without danger of
                                                                                              Caution the customer on the hazards of trying to roll a cart with small
                                                                                              casters across thresholds or deep pile carpets.
   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            7.    Caution customers against using a cart or stand that has not been listed
   a .15 mfd 150V AC type capacitor between a known good earth ground                         by Underwriters Laboratories, Inc. for use with its specific model of
   water pipe, conduit, etc.) and the exposed metallic parts, one at a time.                  television receiver or generically approved for use with TVs of the same or
   Measure the AC voltage across the combination of 1500 ohm resistor and                     larger screen size.
   .15 mfd capacitor. Reverse the AC plug by using a non-polarized adaptor              8.    Caution customers against using extension cords. Explain that a forest of
   and repeat AC voltage measurements for each exposed metallic part. Voltage                 extensions, sprouting from a single outlet, can lead to disastrous
   measured must not exceed 0.75 volts RMS. This corresponds to 0.5 milliamp                  consequences to home and family.
   AC. Any value exceeding this limit constitutes a potential shock hazard and
   must be corrected immediately.

  PV154 - 923-03506                                                                 i                                                             ZP26/28 - SAFETY
CRT ANODE HIGH VOLTAGE MEASUREMENT PROCEDURE                                  5. Do not use freon-propelled chemicals. These can generate electri-
                                                                              cal charge sufficient to damage ES devices.
To prevent possible exposure to radiation caused by excessive CRT
Anode voltage, the High Voltage Shutdown circuit senses the level             6. Do not remove a replacement ES device from its protective pack-
of flyback pulse from "Flyback Transformer" representative of the             age until immediately before you are ready to install t.(Most replace-
actual high voltage on the CRT anode. When this level exceeds a               ment ES devices are packaged with leads electrically shorted to-
predetermined voltage, the circuit shuts down the horizontal drive,           gether by conductive foam, aluminum foil, or comparable conduc-
preventing further generation of anode voltage. In this condition,            tive material.)
the horizontal drive is "latched" off. The drive will remain off until        7. Immediately before removing the protective material from the
power (via remote control or front panel) is re-cycled from "Off" to          leads of a replacement ES device, touch the protective material to
"On".                                                                         the chassis or circuit assembly into which the device will be in-
Critical Safety components (designated with an "X" in the compo-              stalled.
nent designator) are designed to operate the CRT at a safe operating          Caution: Be sure no power is applied to the chassis or circuit, and
Anode voltage and provide proper shutdown thresholds . If replace-            observe all other safety precautions.
ment of any of these components are deemed necessary, it is impor-            8. Minimize bodily motions when handling unpackaged replace ment
tant to use original type Zenith replacement components. After                ES devices. (Otherwise, seemingly harmless motion, such as the brush-
replacement is made, confirm proper Anode voltage using the fol-              ing together of your clothing or the lifting of your foot from a
lowing procedure.                                                             carpeted floor, can generate static electricity sufficient to damage
Measurement of the CRT Anode voltage must be performed using a                an ES device.)
high impedance high voltage meter, with no visible raster on the              REGULATORY INFORMATION
screen, and operating at nominal horizontal scanning frequency.
Connect a strong broadcast signal (or TV signal generator operating           This equipment has been tested and found to comply with the limits
at 15.734kHz horizontal scanning rate) to the RF input.                       for a Class B digital device, pursuant to Part 15 of the FCC Rules.
                                                                              These limits are designed to provide reasonable protection against
After discharging the CRT, connect a high impedance high voltage              harmful interference when the equipment is operated in a residential
meter to the CRT anode. Turn the television "on" and confirm a good           installation. This equipment generates, uses and can radiate radio
signal is being displayed . Reduce Brightness and Contrast settings           frequency energy and, if not installed and used in accordance with
until the picture is well extinguished. If the voltage reading is             the instruction manual, may cause harmful interference to radio
higher than the maximum, verify circuit component values and                  communications. However, there is no guarantee that interference
proper operation.                                                             will not occur in a particular installation. If this equipment does
                                                                              cause harmful interference to radio or television reception, which
     B+ VDC                HV NOM              HV MAX
                                                                              can be determined by turning the equipment off and on, the user is
    (0 BEAM)                 KV                  KV
                                                                              encouraged to try to correct the interference by one or more of the
   115 +/- 2%               30.2                30.5                          following measures: Reorient or relocate the receiving antenna; In-
SHUTDOWN TEST PROCEDURE                                                       crease the separation between the equipment and receiver; Connect
                                                                              the equipment into an outlet on a circuit different from that to
Equipment needed is a video generator, HV DC meter (0 to 40 KV,
                                                                              which the receiver is connected; Consult the dealer or an experi-
high Z), and a external variable power supply (0V to 6VDC @ 5Amps
                                                                              enced radio/TV technician for help.
                                                                              The presence of the DTV certification mark indicates that this prod-
To verify the Shutdown Circuit is operating properly, Supply +6V DC
                                                                              uct will successfully receive digital television transmissions that
to pin 1 of P1407 and ground to Heat sink of Q1413. If there is no
                                                                              conform to any and all of the video formats described in the ATSC
raster and set goes into Shutdown, then the Shutdown Circuit is
                                                                              Digital Television Standard.
functional. If the set doesn't go into Shutdown, then the Circuit is
defective.                                                                    The responsible party for this device's compliance is:
                                                                              Zenith Electronics Corporation
ELECTROSTATICALLY SENSITIVE DEVICES                                           201 James Record Road
Some semiconductor (solid-state) devices can be damaged easily by             Huntsville, AL 35824, USA
static electricity. Such components commonly are called Electro-              Digital TV Hotline: 1-800-243-0000
statically Sensitive (ES) Devices. Examples of typical ES devices are
integrated circuits and some field-effect transistors and semicon-            TRADEMARKS USED IN THIS MANUAL
ductor "chip" components. The following techniques should be                  Dolby Digital

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