LG ZLD15A1 Service Manual

SERVICE MANUAL

Product Type: LCD TV
Chassis: ZLD
Manual Series: CM153
Manual Part #: 923-03443R1
Model Line: D
Product Year: 2001

Model Series:

ZLD15A1
ZLD20A1

Printed in U.S.A.
ZLD20 CCI 2.5k

CONTENTS

General Info/Remotes .................................... 1

Installer’s Menu.............................................2

Servicing/Troublshooting...............................3

Module/Model Part Lists................................. 4

Exploded Views ............................................. 5

Schematics/PCB Layouts................................. 6

Published by Technical Publications

Zenith Electronics Corporation

P.O. Box 240007

Huntsville, Alabama 35824

Copyright ? April 2001 by Zenith Electronics Corporation

A

0

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PRODUCT SAFETY SERVICING GUIDELINES FOR AUDIO-VIDEO PRODUCTS

IMPORTANT SAFETY NOTICE

This manual was prepared for use only by properly trained audio­visual 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. If
any fuse (or Fusible Resistor) in this TV receiver is blown, replace it
only with the factory specified fuse type and rating. When replacing
a high wattage resistor (Oxide Metal Film Resistor, over 1W), keep the
resistor 10mm away from PCB. Always keep wires away from high
voltage or high temperature parts.

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. Service work should be performed
only after you are thoroughly familiar with these safety checks and
servicing guidelines.

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.

GENERAL GUIDANCE

An lsolation Transformer should always be used during the servicing
of a receiver whose chassis is not isolated from the AC power line. Use
a transformer of adequate power rating to protect against personal
injury from electrical shocks. It will also protect the receiver and it’s
components from being damaged by accidental shorts of the circuitry
that may be inadvertently introduced during the service operation.

Before returning the receiver to the customer, always perform an AC
leakage current check on the exposed metallic parts of the cabinet,
such as antennas, terminals, etc., to be sure the set is safe to operate
without damage of electrical shock.

LEAKAGE CURRENT COLD CHECK (ANTENNA COLD CHECK)

With the instrument AC plug removed from AC source, connect an
electrical jumper across the two AC plug prongs. Place the AC switch
in the on position, connect one lead of ohm-meter to the AC plug
prongs tied together and touch other ohm-meter lead in turn to
each exposed metallic parts such as antenna terminals, phone jacks,
etc. If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1M½ and 5.2M½. When the
exposed metal has no return path to the chassis the reading must be
infinite. Any other abnormality that exists must be corrected before
the receiver is returned to the customer.

LEAKAGE CURRENT HOT CHECK (SEE BELOW FIGURE)

Plug the AC cord directly into the AC outlet. Do not use a line
Isolation Transformer during this check. Connect 1.5K/10watt resistor
in parallel with a 0.15uF capacitor between a good earth ground
(Water Pipe, Conduit, etc.) and the exposed metallic parts. Measure
the AC voltage across the resistor using AC voltmeter with 1000
ohms/volt or more sensitivity. Reverse plug the AC cord into the AC
outlet and repeat AC voltage measurements for each exposed metallic
part. Any voltage measured must not exceed 0.75 volt RMS at 0.5mA.
In case any measurement is out of the limits specified, there is the
possibility of shock hazard and the set must be checked and repaired
before it is returned to the customer.

LEAKAGE CURRENT HOT CHECK CIRCUIT

.C. Voltmeter

Good Earth Ground
such as the Water
Pipe, Conduit, etc.

0.15uF

1500 OHM

WATT

1

Place this probe
on each expose
metal part.

REGULATORY INFORMATION

This equipment, trade name Zenith, model number, IQD27D53T, 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 equipment 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 equipment 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 equipment 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 compliance is:
Zenith Electronics Corporation
201 James Record Road
Huntsville, AL 35824, USA
Digital TV Hotline:
1-800-243-0000
Dolby Digital® Manufactured under license from Dolby Laboratories.

“Dolby” and the double-D symbol are trademarks of Dolby
Laboratories. Confidential Unpublished Works.

©1992-1997 Dolby Laboratories, Inc. All rights reserved.
The presence of the DTV certification mark indicates that this product

will successfully receive digital television transmissions that conform
to any and all of the video formats described in the ATSC Digital
Television Standard.

VCR Plus+, PlusCode and GUIDE Plus+ are trademarks of Gemstar
Development Corporation. The VCR Plus+ and GUIDE Plus+ systems
are manufactured under license from Gemstar Development
Corporation and VCR Index Systems B.V., respectively.

Gemstar is not in any way liable for the accuracy of the program
schedule information provided by the GUIDE Plus+ system. In no
event shall Gemstar be liable for any amounts representing loss of
profits, loss of business, or indirect, special, or consequential damages
in connection with the provision or use of any information,
equipment, or services relating to the GUIDE plus+ system.

923-03443R1 2 ZLDA1

T ABLE OF CONTENTS

T ABLE OF CONTENTS ..............................................2

SERVICING PRECAUTIONS....................................... 3

ADJUSTMENTS ..................................................... 5

TROUBLE SHOOTING.............................................. 7

PARTS LIST .......................................................... 8

EXPLODED VIEW ...................................................14

BLOCK DIAGRAM ..................................................15

PCB MAIN (TOP VIEW) ..........................................16

PCB MAIN (BOTTOM VIEW)..................................... 17

PCB LAYOUT CONTROL & TUNER.............................. 18

SCHEMATIC ......................................................... 19

CM152 3 ZLDA1

SERVICING

SERVICING PRECAUTIONS

CAUTION: Before servicing receivers covered by this service
manual and its supplements and addenda, read and follow
the SAFETY PRECAUTIONS on page 3 of this publication.
NOTE: If unforeseen circumstances create conflict between
the following servicing precautions and any of the safety
precautions on page 3 of this publication, always follow
the safety precautions. Remember: Safety First.

GENERAL SERVICING PRECAUTIONS

1. Always unplug the receiver AC power cord from the
AC power source before performing the following.

a. Removing or reinstalling any component,

circuit board module or any other receiver
assembly.

b. Disconnecting or reconnecting any receiver

electrical plug or other electrical connection.

c. Connecting a test substitute in parallel with

an electrolytic capacitor in the receiver.

2. Test high voltage only by measuring it with an ap­propriate high voltage meter or other voltage-mea­suring device (DVM, FETVOM, etc) equipped with a
suitable high voltage probe. Do not test high volt­age by “drawing an arc”.

3. Discharge the picture tube anode only by (a) first
connecting one end of an insulated clip lead to the
degaussing or kine aquadag grounding system shield
at the point where the picture tube socket ground
lead is connected, and then (b) touch the other end
of the insulated clip lead to the picture tube anode
button, using an insulating handle to avoid personal
contact with high voltage.

4. Do not spray chemicals on or near this receiver or
any of its assemblies.

5. Unless specified otherwise in this service manual,
clean electrical contacts only by applying the follow­ing mixture to the contacts with a pipe cleaner, cot­ton-tipped stick or comparable nonabrasive applica­tor; 10% (by volume) Acetone and 90% (by volume)
isopropyl alcohol (90%-99% strength)

CAUTION: This is a flammable mixture. Unless specified

otherwise in this service manual, lubrication of con­tacts in not required.

6. Do not defeat any plug/socket B+ voltage interlocks
with which receivers covered by this service manual
might be equipped.

7. Do not apply AC power to this instrument and/or any
of its electrical assemblies unless all solid-state de­vice heat sinks are correctly installed.

8. Always connect the test receiver ground lead to the
receiver chassis ground before connecting the test
receiver positive lead. Always remove the test receiver
ground lead last.

9. Use with this receiver only the test fixtures specified
in this service manual.

CAUTION: Do not connect the test fixture ground strap

to any heatsink in this receiver.

ELECTROSTATIC SENSITIVE (ES) DEVICES

Some semiconductor (solid state) devices can be
damaged easily by static electricity. Such components
commonly are called Electrostatic Sensitive Devices.
Examples of typical ES devices are integrated circuits
and some field effect transistors and semiconductor “chip”
components. The following techniques should be used
to help reduce the incidence of component damage
caused by static electricity.

1. Immediately before handling any semiconductor com­ponent or semiconductor-equipped assembly, drain
off any electrostatic charge on your body by touch­ing a known earth ground. Alternatively, obtain and
wear a commercially available discharging wrist strap
device, which should be removed to prevent poten­tial shock reasons prior to applying power to the
unit under test.

2. After removing an electrical assembly equipped with
ES devices, place the assembly on a conductive sur­face such as aluminum foil, to prevent electrostatic
charge buildup or exposure of the assembly.

3. Use only a grounded-tip soldering iron to solder or
unsolder ES devices.

4. Use only an anti-static type solder removal device.
Some solder removal devices not classified as “anti­static” can generate electrical charges sufficient to
damage ES devices.

5. Do not use freon-propelled chemicals. These can gen­erate electrical charges sufficient to damage ES de­vices.

6. Do not remove a replacement ES device from its pro­tective package until immediately before you are ready
to install it. (Most replacement ES devices are pack­aged with leads electrically shorted together by con­ductive foam, aluminum foil or comparable conduc­tive material).

7. Immediately before removing the protective material
from the leads of a replacement ES device, touch the
protective material to the chassis or circuit assembly
into which the device will be installed.

CAUTION: Be sure no power is applied to the chassis or

circuit, and observe all other safety precautions.

8. Minimize bodily motions when handling unpackaged
replacement ES devices. (Otherwise harmless motion
such as the brushing together of your clothes fabric
or the lifting of your foot from a carpeted floor can
generate static electricity sufficient to damage an
ES device.)

CM153 - 923-03443R1 4 ZLD20A1 - SERVICING

SERVICING

GENERAL SOLDERING GUIDELINES

1. Use a grounded-tip, low-wattage soldering iron and
appropriate tip size and shape that will maintain tip
temperature within the range or 500cF to 600cF.

2. Use an appropriate gauge of RMA resin-core solder
composed of 60 parts tin/40 parts lead.

3. Keep the soldering iron tip clean and well tinned.

4. Thoroughly clean the surfaces to be soldered. Use a
mall wire bristle (0.5 inch, or 1.25cm) brush with a
metal handle. Do not use freon-propelled spray-on
cleaners.

5. Use the following unsoldering technique

a. Allow the soldering iron tip to reach normal

temperature. (500cF to 600cF)

b. Heat the component lead until the solder

melts.

c. Quickly draw the melted solder with an anti-

static, suction-type solder removal device or
with solder braid. CAUTION: Work quickly to
avoid overheating the circuit board printed
foil.

6. Use the following soldering technique.

a. Allow the soldering iron tip to reach a normal

temperature (500cF to 600cF)

b. First, hold the soldering iron tip and solder

the strand against the component lead until
the solder melts.

c. Quickly move the soldering iron tip to the

junction of the component lead and the
printed circuit foil, and hold it there only
until the solder flows onto and around both
the component lead and the foil.
CAUTION: Work quickly to avoid overheating
the circuit board printed foil.

d. Closely inspect the solder area and remove any

excess or splashed solder with a small wire­bristle brush.

IC REMOVE/REPLACEMENT

Some chassis circuit boards have slotted holes (oblong)
through which the IC leads are inserted and then bent
flat against the circuit foil. When holes are the slotted
type, the following technique should be used to remove
and replace the IC. When working with boards using the
familiar round hole, use the standard technique as
outlined in paragraphs 5 and 6 above.

REMOVAL

1. Desolder and straighten each IC lead in one opera­tion by gently prying up on the lead with the solder­ing iron tip as the solder melts.

2. Draw away the melted solder with an anti-static suc­tion-type solder removal device (or with solder braid)
before removing the IC.

REPLACEMENT

1. Carefully insert the replacement IC in the circuit
board.

2. Carefully bend each IC lead against the circuit foil
pad and solder it.

3. Clean the soldered areas with a small wire-bristle brush.
(It is not necessary to reapply acrylic coating to the
areas).

“SMALL-SIGNAL” DISCRETE TRANSISTOR

REMOVAL/REPLACEMENT

1. Remove the defective transistor by clipping its leads
as close as possible to the component body.

2. Bend into a “U” shape the end of each of three leads
remaining on the circuit board.

3. Bend into a “U” shape the replacement transistor
leads.

4. Connect the replacement transistor leads to the cor­responding leads extending from the circuit board
and crimp the “U” with long nose pliers to insure
metal to metal contact then solder each connection.

POWER OUTPUT, TRANSISTOR DEVICE

REMOVAL/REPLACEMENT

1. Heat and remove all solder from around the transistor
leads.

2. Remove the heatsink mounting screw (if so equipped).

3. Carefully remove the transistor from the heat sink of
the circuit board.

4. Insert new transistor in the circuit board.

5. Solder each transistor lead, and clip off excess lead.

6. Replace heatsink.

DIODE REMOVAL/REPLACEMENT

1. Remove defective diode by clipping its leads as close
as possible to diode body.

2. Bend the two remaining leads perpendicular to the
circuit board.

3. Observing diode polarity, wrap each lead of the new
diode around the corresponding lead on the circuit
board.

4. Securely crimp each connection and solder it.

5. Inspect (on the circuit board copper side) the solder
joints of the two “original” leads. If they are not
shiny, reheat them and if necessary, apply additional
solder.

FUSE AND CONVENTIONAL RESISTOR

REMOVAL/REPLACEMENT

1. Clip each fuse or resistor lead at top of the circuit
board hollow stake.

2. Securely crimp the leads of replacement component
around notch at stake top.

CM153 - 923-923-03443R1 5 ZLD20A1 - SERVICING

SERVICING

3. Solder the connections.
CAUTION: Maintain original spacing between the

replaced component and adjacent components
and the circuit board to prevent excessive
component temperatures.

CIRCUIT BOARD FOIL REPAIR

Excessive heat applied to the copper foil of any printed
circuit board will weaken the adhesive that bonds the
foil to the circuit board causing the foil to separate
from or “lift-off” the board. The following guidelines
and procedures should be followed whenever this
condition is encountered.

AT IC CONNECTIONS

To repair a defective copper pattern at IC connections
use the following procedure to install a jumper wire on
the copper pattern side of the circuit board. (Use this
technique only on IC connections).

1. Carefully remove the damaged copper pattern with a

sharp knife. (Remove only as much copper as abso­lutely necessary).

2. carefully scratch away the solder resist and acrylic

coating (if used) from the end of the remaining cop­per pattern.

3. Bend a small “U” in one end of a small gauge jumper

wire and carefully crimp it around the IC pin. Solder
the IC connection.

4. Route the jumper wire along the path of the out-

away copper pattern and let it overlap the previously
scraped end of the good copper pattern. Solder the
overlapped area and clip off any excess jumper wire.

AT OTHER CONNECTIONS

Use the following technique to repair the defective cop-

per pattern at connections other than IC Pins. This
technique involves the installation of a jumper wire
on the component side of the circuit board.

1. Remove the defective copper pattern with a sharp

knife. Remove at least ¼ inch of copper, to ensure
that a hazardous condition will not exist if the jumper
wire opens.

2. Trace along the copper pattern from both sides of

the pattern break and locate the nearest component
that is directly connected to the affected copper
pattern.

3. Connect insulated 20-gauge jumper wire from the lead

of the nearest component on one side of the pattern
break to the lead of the nearest component on the
other side. Carefully crimp and solder the connec­tions. CAUTION: Be sure the insulated jumper wire is
dressed so the it does not touch components or sharp
edges.

CM153 - 923-03443R1 6 ZLD20A1 - SERVICING

SECTION 1

OVERVIEW

SERVICING

ADJUSTMENTS

This set uses an adapter, so connect the adapter and the
set correctly before adjustment. The adjustment must
be performed under the correct sequence.

The adjustment must be performed in the circumstance
of 25+/-5cC of temperature 65+/-10% of relative
humidity if there is no specific designation. The input
voltage of the receiver must keep 220V, 60Hz in adjusting.
The set must be operated for 30 minutes preliminarily
before adjustment if there is no specific designation.

Note: Heat Run must be performed with the full white signal

or TV noise signal in the internal part of the set. The
time for Heat Run can be changed owing to production
plan.

DVCO ADJUSTMENT

Turn the TV on.
(2) Receive the Digital Pattern.
3-2. Adjustment
(1) Select DVCO ADJ by pressing ADJ Key(or SVC Key) of
Remote Control for Adjustment.
(2) Press the VOL + Key repeatly to appear ÒOKÓ.

USING METHOD FOR CA-110

CA110

Screen

30[cm]

LCD TV

Input signal of Video

NTSC 13 CH

AUTO RGB ADJUSTMENT

4-1. Preparation for Adjustment
(1) Adjust it after performing DVCO Adjustment.
(2) Receive the Digital Pattern.
4-2. Adjustment
(1) Select AUTO RGB ADJ by pressing ADJ Key(or SVC

Key)
of Remote Control for Adjustment.
(2) Press the VOL + Key repeatly to appear ÒOKÓ.

RGB LEVEL ADJUSTMENT

5-1. Using Equipment
(1) Pattern Generator(408NPS-READER) which 10 STEP

is possible.
(2) A Remote Control for Adjustment 5-2. Adjustment
(1) Select RGB LEVEL by pressing ADJ Key(or SVC Key) of
Remote Control for Adjustment.
(2) Select it by using VOL + Key.
(3) Adjust that until 9th and 10th STEP is

undistinguished by using VOL +/- Key in R-DRIVE item.
(4) Adjust G-DRIVE and B-DRIVE as same way.
(5) When adjustment is finished, escape it by pressing
ENTER Key.

CM153 - 923-03443R1 7 ZLD20A1 - SERVICING

ADJUSTMENT INSTRUCTIONS ZLD15A1

1. Application Object

This instruction is for the application to the LCD TV.

2. Notes

(1) This set uses an adapter, so connect the adapter and the

set correctly before adjusting.

(2) The adjustment must be performed in the correct

sequence.

(3) The adjustments must be performed in the circumstance of

25+ 5 C of temperature and 65 10% of relative humidity
unless otherwise specified.

(4) The input voltage of the receiver must be 220V, 60Hz

during adjustment.

(5) The set must be operated for 30 minutes preliminarily

before adjustment unless otherwise specified.

* "Heat Run" must be performed with the full white signal or TV

noise signal in the internal part of the set.

3. TV Mode Adjustment

Before entering into the adjustment mode set the TV up with
the MENU button as below.

Contrast 85
Brightness 100
Saturation 50
Tint 0

Low Light(Black)

IC
VPC3230D
VPC3230D
VPC3230D

Brightness:[cd/m^2]

IIC Type

IIC 0x52/7:0/

IIC 0x30/11:0/

Fp 0xDC

x
y

Red

0.63

0.34

Name

BR

ACC_Sat

Tint

Green

0.30

0.60

Default

2930

0

0

Blue

0.14

0.10

Unit-Decimal

Adj. Mode

No.304

No.236~237

No.248

White

0.32

0.34

150[cd/m^2]

4. PC Input Mode Adjustment

4-1. Required Test Equipment

(1) A pattern generator being in proportion to VG819 ; Pattern

of 64 tones

(2) A remote control

4-2. Preparation for Adjustment

(1) Perform "Heat Run" for more than 30 minutes in white

pattern.

(2) Connect the signal of pattern generator to LCD TV.

(3) Lean the set 45 backward. (Adjustment is easy.)

45

3-1. White Balance Adjustment

3-1-1. Required Test Equipment

(1) A Remote Control
(2) A Color Analyzer for LCD : CA-110
(3) A TV Signal Generator : Pattern of 64 (128) tones or Ch. 13

in the company.

3-1-2. Preparation for Adjustment

(1) This adjustment should be performed 30 minutes later

after "Heat Run".

(2) This adjustment should be performed in a darkroom or in

the simmilar condition.

3-1-3. Low Light Adjustment

(1) Seletc Ch.13 .
(2) Enter into the adjustment mode with the ADJ button.
(3) Select the Sub-bright and stop adjusting at the moment

when Gray 0 and 1 are not distinguished.

CM153 8 ZLD15A1

(4) Set the PC mode menu as below.

Initial Value

Contrast

70

Brightness

100

4-3. White Adjustment

(1) Approve the signal of 64 tones of XGA(1024 * 768).
(2) Select all the gain of R, B and G with using ADJ of remote

control.

(3) After making 62 tones, 63 tones and 64 tones not

distinguished with using each signal of R, G and B, finish
adjusting at the moment when the signal 62, 63 and 64 is
distinguished.

R

Color Coordinates(x,y)

AD9884

0.63 0.34
0x02

G

0.30 0.60
0x03

B

0.14 0.10
0x04

+/-0.03

Register

Error