Zenith C32V23 - 32" Flat-Screen Integrated HDTV User manual

SERVICE MANUAL
Product Type: Directview HDTV
Chassis: AB
Manual Series: CM154
Manual Part #: 923-03497
Model Line: E
Product Year: 2002
Overview ...................................................... 1
Service Menu ................................................ 2
Servicing ..................................................... 3
Parts ........................................................... 4
Diagrams ...................................................... 5
Schematics ................................................... 6
Published September 2002
by Technical Publications
Zenith Electronics Corporation
201 James Record Road
Huntsville, Alabama 35824-1513
Copyright  2002 by Zenith Electronics Corporation
Model Series:
CONTENTS
C32V23

PV154 - 923-03497 AB - 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 x-radiation, 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
components, 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 TRANS-
FORMER 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 be-
tween 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 measure-
ments 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.
X-RADIATION
1. Be sure procedures and instructions to all service personnel cover the
subject of x-radiation. The only potential source of x-rays in current TV
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
applicable schematic. Operation at higher voltages may cause a failure of
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.
3. It is essential that the service personnel have available an accurate and
reliable high-voltage meter.
4. When the high-voltage circuitry is operating properly, there is no possibility
of an x-radiation problem. Every time a chassis is serviced, the brightness
should be run up and down while monitoring the high voltage with a
meter, to be certain that the high voltage does not exceed the specified
value and that it is regulating correctly.
5. When troubleshooting and making test measurements in a product with a
problem of excessively high voltage, avoid being unnecessarily close to
the picture tube and the high voltage power supply. Do not operate the
product longer than necessary to locate the cause of excessive voltage.
6. Refer to HV, B+, and shutdown adjustment procedures described in the
appropriate schematics and diagrams (where used).
IMPLOSION
1. All direct view picture tubes are equipped with an integral implosion
protection system; take care to avoid damage during installation.
2. Use only the recommended factory replacement tubes.
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.
A.C. Voltmeter
1500 OHM
10 WATT
Place this probe
on each exposed
metal part.
Good Earth Ground
such as the Water
Pipe, Conduit, etc.
0.15uF

PV154 - 923-03497 AB - SAFETY
ii
PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS
X-RADIATION
To prevent possible exposure to x-radiation caused by excessive CRT
Anode voltage, the AB Chassis incorporate a “High Voltage Shutdown”
circuit. This circuit senses the level of flyback pulse from the “Flyback
Transformer” representative of the actual high voltage on the CRT anode.
When this level exceeds a predetermined voltage, the circuit shuts down
the horizontal drive, preventing further generation of anode voltage. In
this condition, the horizontal drive is “latched” off for about 5 seconds,
after which, restart is attempted.
SHUTDOWN CIRCUIT OPERATION
The flyback pulse voltage from Pin 6 of TX3201 (Flyback Transformer) is
peak detected (rectified) by the action of diode D3000 and capacitor
C3001. This form a DC voltage appearing on C3001 representative of the
CRT anode voltage (HV) produced by T3201. This voltage is divided down
by precision resistors RX3001, RX3002, & RX3003. This lower voltage,
appear on the positive input (pin 5) of IC3101.
If the even CRT anode voltage become excessive, in IC3101 the positive
input (pin 5) will be higher than negative input of pin 6 and therefore
his output (pin 7) will go to high level, at approximately 15 volts. This
signal (SHUTDOWN) is send to Base of Q3201 causing Horizontal Drive to
be disabled and latched causing HV goes down. In about 5 seconds, the
shutdown reset circuit (Pins 8, 9 & 14 of IC3100) enable again the
Horizontal Drive and HV must be reestablished. If the shutdown condi-
tion persist the circuit goes into hiccup mode.
The circuit formed by Q3104, C3113, C3108, D3107, R3131, R3132, R3133
and R3134 disable the HV compensation output (Q3102-B signal) during
turn on and shutdown conditions (transients).
CRT ANODE HIGH VOLTAGE MEASUREMENT PROCEDURE
Each CRT screen size has it’s own safe operating anode and shutdown
voltage. Critical safety component (designated with an ‘X’ in the compo-
nent designator) are designed to operate the CRT at a safe operating
anode voltage and provide proper shutdown thresholds. If replacement
of any of these components are deemed necessary, it is important to use
original type Zenith components. After replacement is made, confirm
proper anode voltage using the following procedure.
Measurement of the CRT anode voltage must be performed using a high
impedance-high voltage meter, with no raster on the screen, and operat-
ing at nominal horizontal frequency, 33.75 Khz (HDTV signal).
After discharging the CRT, connect a high impedance-high voltage meter
to the CRT anode. Turn the television ‘on’ and confirm a good signal is
being displayed. Reduce Brightness and Contrast settings until the
picture is well extinguished.
Observe the anode voltage meter reading and compare with the table
below for the proper CRT screen size. If the voltage reading is higher
than the maximum, verify circuit component values and proper opera-
tion.
CRT Screen
Size
Nominal Anode
Voltage
(
KV
)
Max. Shutdown
Voltage
(
KV
)
32” 30 ± 0.5 36
36” 30 ± 0.5 36
34” Wide 30 ± 0.5 36
CRT Anode Voltage
HV SHUTDOWN PROCEDURE
Adjust beam current to 0 mA. Connect a variable Resistor (10 MW)
between pin 2 and pin 3 of 2W6 connector, and decrease slowly the
resistance value from 10 MW to 0 W. Measure shutdown HV. Increase the
resistance value to 10 MW. After 5 seconds, approximately, verify that
the HV must be reestablished (High Voltage Reset).
Components and Factory Menu registers with any influence in HV in-
crease.
• C3109
• C3115
• CX3204
• CX3208
• CX3210
• L3200
• RX3335
• TX3100
• 40 Vcd
• H_SIZE REGISTER

TABLE OF CONTENTS
PV154 - 923-03497 AB - CONTENTS
SECTION 1 .............................. 1-1
OVERVIEW.............................................. 1-1
INTRODUCTION ................................... 1-1
FEATURES ........................................... 1-1
CONNECTIONS ......................................... 1-2
REAR JACKS ........................................ 1-2
FRONT JACKS ...................................... 1-2
REMOTE CONTROL .................................... 1-3
REMOTE BUTTON DESCRIPTIONS ............. 1-3
PROGRAMMING THE REMOTE .................. 1-3
REMOTE CODES ..................................... 1-4
OPERATING MODE KEY FUNCTIONS .......... 1-7
USER MENUS .......................................... 1-9
DTV SET UP MENU ................................ 1-9
DTV VIDEO MENU ................................. 1-9
DTV AUDIO MENU ................................. 1-9
DTV TIME MENU ................................... 1-9
DTV SPECIAL MENU .............................. 1-9
DTV LOCK MENU ................................. 1-10
ATV USER'S INTERFACE ....................... 1-10
ATV SETUP MENU ............................... 1-10
ATV VIDEO MENU ............................... 1-10
ATV AUDIO MENU ............................... 1-10
SECTION 2 .............................. 2-1
SERVICE MENU OPTIONS .......................... 2-1
SERVICE MENU ADJUSTMENTS ................... 2-6
SECTION 3 .............................. 3-1
CIRCUIT OVERVIEW ................................. 3-1
LARGE SIGNAL MODULE ........................ 3-1
SMALL SIGNAL MODULE ........................ 3-7
GEOMETRY ADJUSTMENTS ....................... 3-10
TROUBLESHOOTING ................................ 3-16
SECTION 4 .............................. 4-1
PARTS .................................................... 4-1
SECTION 5 .............................. 5-1
34” EXPLODED VIEW ................................ 5-1
32/36” EXPLODED VIEW ........................... 5-2
INTERCONNECT DIAGRAM ......................... 5-3
BLOCK DIAGRAM ...................................... 5-4
TOC-1
SECTION 6 .............................. 6-1
POWER SUPPLY CIRCUIT ........................... 6-1
DEFLECTION & HV CIRCUIT ....................... 6-2
DYNAMIC FOCUS CIRCUIT .......................... 6-3
AC/DC INPUT CIRCUIT ............................. 6-4
SLAVE POWER SUPPLY CIRCUIT ................. 6-5
SCAN BOOST CONTROLLER CIRCUIT ............ 6-6
SHUTDOWN & COMPENSATION CIRCUIT ....... 6-7
KEYBOARD CIRCUIT ................................. 6-8
32” FRONT JACKPACK CIRCUIT .................. 6-9
34” FRONT JACKPACK CIRCUIT ................ 6-10
POWER LED & IR RECEIVER CIRCUIT......... 6-11
VIDEO OUTPUT CIRCUIT ......................... 6-12
SCAN VELOCITY CIRCUIT ........................ 6-13
MAIN PCB TOP ...................................... 6-14
MAIN PCB BOTTOM ................................. 6-15
POWER SUPPLY PCB TOP ......................... 6-16
POWER SUPPLY PCB BOTTOM ................... 6-17
ONE PANEL PCB TOP .............................. 6-18
ONE PANEL PCB BOTTOM ......................... 6-19