TOSHIBA 42WLT66 Service Manual

SERVICE MANUAL

LCD Color Television

42WLT66

Ver. 1

This model is classified as a green product (*1), as indicated by the underlined serial number.
This Service Manual describes replacement parts for the green product. When repairing this
green product, use the part(s) described in this manual and lead-free solder (*2).
For (*1) and (*2), refer to GREEN PRODUCT PROCUREMENT and LEAD-FREE

SOLDER.

© TOSHIBA CORPORATION

IMPORTANT NOTICE

WARNING:

You are requested that you shall not modify or alter the information or data
provided herein without prior written consent by Toshiba. Toshiba shall not
be liable to anybody for any damages, losses, expenses or costs, if any,
incurred in connection with or as a result of such modification or alteration.

THE INFORMATION OR DATA HEREIN SHALL BE PROVIDED "AS IS"
WITHOUT ANY WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED
WARRANTY OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE.

Toshiba shall not be liable for any damages, losses, expenses or costs, if
any, incurred in connection with or as a result of use of any information or
data provided herein.

GREEN PRODUCT PROCUREMENT

p

p

The EC is actively promoting the WEEE & RoHS Directives that define standards for
recycling and reuse of Waste Electrical and Electronic Equipment and for the Restriction of
the use of certain Hazardous Substances. From July 1, 2006, the RoHS Directive will

rohibit any marketing of new products containing the restricted substances.

Increasing attention is given to issues related to the global environmental. Toshiba
Corporation recognizes environmental protection as a key management tasks, and is doing its
utmost to enhance and improve the quality and scope of its environmental activities. In line
with this, Toshiba proactively promotes Green Procurement, and seeks to purchase and use

roducts, parts and materials that have low environmental impacts.

Green procurement of parts is not only confined to manufacture. The same green parts used
in manufacture must also be used as replacement parts.

LEAD-FREE SOLDER

p

p

This product is manufactured using lead-free solder as a part of a movement within the
consumer products industry at large to be environmentally responsible. Lead-free solder must
be used in the servicing and repair of this product.

WARNING: This product is manufactured using lead free solder.

DO NOT USE LEAD BASED SOLDER TO REPAIR THIS PRODUCT!

The melting temperature of lead-free solder is higher than that of leaded solder by 86ºF to
104ºF (30ºC to 40ºC). Use of a soldering iron designed for lead-based solders to repair

roduct made with lead-free solder may result in damage to the component and or PCB being

soldered. Great care should be made to ensure high-quality soldering when servicing this

roduct especially when soldering large components, through-hole pins, and on PCBs as the

level of heat required to melt lead-free solder is high.

SAFETY INSTRUCTION

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "SAFETY

PRECAUTION" AND "PRODUCT SAFETY NOTICE" INSTRUCTIONS BELOW.

Safety Precaution

WARNING: SERVICING SHOULD NOT BE ATTEMPTED BY ANYONE

UNFAMILIAR WITH THE NECESSARY PRECAUTIONS ON THIS RECEIVER.
THE FOLLOWING ARE THE NECESSARY PRECAUTIONS TO BE OBSERVED
BEFORE SERVICING THIS CHASSIS.

1. An isolation transformer should be connected in the power line between the receiver
and the AC line before any service is performed on the receiver.

2. Always disconnect the power plug before any disassembling of the product. It may
result in electrical shock.

3. When replacing a chassis in the cabinet, always be certain that all the protective
devices are put back in place, such as nonmetallic control knobs, insulating covers,
shields, isolation resistor-capacitor network, etc.

4. Always keep tools, components of the product, etc away from the children, These items
may cause injury to children.

5. Depending on the model, use an isolation transformer or wear suitable gloves when
servicing with the power on, and disconnect the power plug to avoid electrical shock
when replacing parts. In some cases, alternating current is also impressed in the
chassis, so electrical shock is possible if the chassis is contacted with the power on.

6. Always use the replacement parts specified for the particular model when making
repairs. The parts used in products require special safety characteristics such as
inflammability, voltage resistance, etc. therefore, use only replacement parts that have

these same characteristics. Use only the specified parts when the mark is indicated
in the circuit diagram or parts list.

7. Parts mounting and routing dressing of wirings should be the same as that used
originally. For safety purposes, insulating materials such as isolation tube or tape are
sometimes used and printed circuit boards are sometimes mounted floating. Also make
sure that wirings is routed and clamped to avoid parts that generate heat and which use
high voltage. Always follow the manufactured wiring routes / dressings.

8. Always ensure that all internal wirings are in accordance before re-assembling the
external casing after a repairing completed. Do not allow internal wiring to be pinched
by cabinets, panels, etc. Any error in reassembly or wiring can result in electrical
leakage, flame, etc., and may be hazardous.

9. NEVER remodel the product in any way. Remodeling can result in improper operation,
malfunction, or electrical leakage and flame, which may be hazardous.

10. Touch current check. (After completing the work, measure touch current to prevent an
electric shock.)

z Plug the AC cord directly into the AC outlet. Do NOT use an isolation transformer

for this check.

z Connect a measuring network for touch currents between each exposed metallic part

on the set and a good earth ground such as a water pipe.

Annex D

(normative)

Measuring network for TOUCH CURRENTS

Resistance values in orms (Ω).

V: Voltmeter or oscilloscope

(r.m.s. or peak reading)

Input resistance : 1 MΩ
Input capacitance : 200 pF

Frequency range : 15 Hz to 1 MHz and d.c. respectively

Note: Appropriate measures should be taken to obtain the correct value in case of non

sinusoidal waveforms.

The measuring instrument is calibrated by comparing the frequency factor of with the
solid line in figure F.2 of IEC 60990 at various frequencies. A calibration curve is
constructed showing the deviation of from the ideal curve as a function of frequency.

TOUCH CURRENT = /500 (peak value).

z The potential at any point (TOUCH CURRENT) expressed as voltage and

does not exceed the following value:

The part or contact of a TERMINAL is not HAZARDOUS LIVE if:

a) The open-circuit voltage should not exceed 35 V (peak) a.c. or 60 V d.c. or, if a) is not

met.

b) The measurement of the TOUCH CURRENT shall be carried out in accordance with

IEC 60990, with the measuring network described in Annex D of this standard.

The TOUCH CURRENT expressed as voltages and , does not exceed the
following values:

- for a.c. : = 35 V (peak) and = 0.35 V (peak);

- for d.c. : = 1.0 V

Note: The limit values of = 0.35 V (peak) for a.c. and = 1.0 V for d.c. correspond to

the values 0.7 mA (peak) a.c. and 2.0 mA d.c.

Product Safety Notice

Many electrical and mechanical parts in this chassis have special safety-related
characteristics. These characteristics are often passed unnoticed by a visual inspection and
the protection afforded by them cannot necessarily be obtained by using replacement
components rated for higher voltage, wattage, etc. Replacement parts which have these
special safety characteristics are identified in this manual and its supplements; electrical
components having such features are identified by the international hazard symbols on the
schematic diagram and the parts list.
Before replacing any of these components, read the parts list in this manual carefully. The
use of substitute replacement parts which do not have the same safety characteristics as
specified in the parts list may create electrical shock, fire, or other hazards.

SAFETY INSTRUCTION

Handling the LCD Module

Safety Precaution

In the event that the screen is damaged or the liquid crystal (fluid) leaks, do not breathe in or
drink this fluid.
Also, never touch this fluid. Such actions could cause toxicity or skin irritation. If this fluid
should enter the mouth, rinse the mouth thoroughly with water. If the fluid should contact the
skin or clothing, wipe off with alcohol, etc., and rinse thoroughly with water. If the fluid
should enter the eyes, immediately rinse the eyes thoroughly with running water.

Precautions for Handling the LCD Module

CAUTION: The metal edges of the LCD module are sharp, handle it with
care.

The LCD module can easily be damaged during disassembly or reassembly; therefore,
always observe the following precautions when handling the module.

1. When attaching the LCD module to the LCD cover, position it appropriately and fasten
at the position where the display can be viewed most conveniently.

2. Carefully align the holes at all four corners of the LCD module with the corresponding
holes in the LCD cover and fasten with screws. Do not strongly push on the module

because any impact can adversely affect the performance. Also use caution when
handling the polarized screen because it can easily be damaged.

3. If the panel surface becomes soiled, wipe with cotton or a soft cloth. If this does not
remove the soiling, breathe on the surface and then wipe again.
If the panel surface is extremely solied, use a CRT cleaner as a cleaner. Wipe off the
panel surface by drop the cleaner on the cloth. Do not drop the cleaner on the panel.
Pay attention not to scratch the panel surface.

4. Leaving water or other fluids on the panel screen for an extended period of time can
result in discoloration or stripes. Immediately remove any type of fluid from the screen.

5. Glass is used in the panel, so do not drop or strike with hard objects. Such actions can
damage the panel.

6. CMOS-LSI circuitry is used in the LCD module, so avoid damage due to static
electricity. When handling the module, use a wrist ground or anchor ground.

7. Do not expose the LCD module to direct sunlight or strong ultraviolet rays for an
extended period of time.

8. Do not store the LCD module below the temperature conditions described in the
specifications. Failure to do so could result in freezing of the liquid crystal due to cold
air or loss of resilience or other damage.

9. Do not disassemble the LCD module. Such actions could result in improper operation.

10. When transporting the LCD module, do not use packing containing epoxy resin
(amine) or silicon resin (alcohol or oxim). The gas generated by these materials can
cause loss of polarity.

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鰏鯗鯛鯲

鯱鰐鰋鯷鯹鰏鰂鯱鰍鰈鰋 鰉鰈鰑鯷鰋

鰏鯗鯛鯱鯱鰐鰍鯷鰋鰄

鯸鯒鯱鰐

鰂鯷鯵鰀鯷鰓

鰏鯗鯛鯳

鰏鯗鯘鯲鰂鰈鰑鯒鯲

鯲鯒鯲
鯛鯝鰉

鯲鯒鯲鯲鯒鯲
鯥鰉鯘鯝鰉

鯲鯒鯲
鯘鯝鰉

鰏鯗鯝鯱鰌鯽鯹鰆鯱鰂

鰌鯽鯹鰆鯱鰂

鯳鰮鰱鰵鰢鰽鰉鰩鰶鰲

鯲鯒鯲
鯛鯝鰉

鯲鯒鯲
鯡鯗鰉 鰉鯳鰄鯳鯽鯱

鰏鯗鯛鯵

鰏鯗鯛鯸

鰏鯗鯘鯱鰉鰮鰹鰢鰱

鯲鯗鯗鯛鯵鰦鰤鰦鰵鰜鰩鰏鰭鰦鰵

衻佷 鯵鯽鯹鯽鰍鯱鰂鰏鰆鯽鰍

鯳鯱鰋鯵

RF

Y

,

VD,CLK

Q

Input
Terminal
(Audio)

CVBS(L/R)
S-VIDEO(L/R)
YCbCr(L/R)

PC_IN(L/R)

HP_AMP

SPEAKER

AV BOARD

TIF

Non

MTS+
APRO
MSP

Sound AMP

Input
Terminal
(Video)

CVBS
S-VIDEO
YCbCr
PC IN

Standby

uCON

SW

SIGNAL BOARD

I2C

Bt601 8Bit
HD

RE

DDR RAM

PANEL

FLI8538

CORTEZ Plus

656

DACAMP

CbCr 16bit

HDMI

Analog

Front

End

(16port)

Digital

Input A

Digital

Input B

VBI Data

Processor

Video

Decoder

I2C

PLL

VOC

MUX

UART

DCDi
MADi

Scaling

2nd
Channel
Process

IR I/F

Cortez

Regulator

OSD

BEP

Micro-

processor

LVD

S

GPI
AD

FLASH ROM

PANEL I/F

I2C

EEPROM

Headphone

+Low B

POWER BOARD

AC INPUT&

Power

HDMI

SCHEMATIC DIAGRAM

Precaution

WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "X-RAY

RADIATION PRECAUTION" FOR DIRECT VIEW CTV ONLY, "SAFETY
PRECAUTION" AND "PRODUCT SAFETY NOTICE" OF THIS MANUAL.

CAUTION: The international hazard symbols " " in the schematic diagram
and the parts list designate components which have special characteristics

important for safety and
should be replaced only with types identical to those in the original circuit
or specified in the parts list.

The mounting position of replacements is to be identical with originals.
Before replacing any of these components, read carefully the SAFETY
PRECAUTION and PRODUCT SAFETY NOTICE.

Do not degrade the safety of the receiver through improper servicing.

Note:

1. RESISTOR
Resistance is shown in ohm [K=1,000, M=1,000,000]. All resistors are 1/6 W and 5 %
tolerance carbon resistor, unless otherwise noted as the following marks.

1/2R : Metal or Metal oxide of 1/2 watt
1/2S : Carbon composition of 1/2 watt
1RF : Fuse resistor of 1 watt
10 W : Cement of 10 watt
K : ±10 %
G : ±2 %
F : ±1 %

2. CAPACITOR

Unless otherwise noted in schematic, all capacitor values less than 1 are expressed in
µF, and the values more than 1 in pF.
All capacitors are ceramic 50 V, unless otherwise noted as the following marks.

= Electrolytic capacitor
= Mylar capacitor

3. The parts indicated with " " have special characteristics, and should be replaced with
identical parts only.

4. Voltages read with DIGITAL MULTI-METER from point indicated to chassis ground,
using a color bar signal with all controls at normal, line voltage at nominal AC volts.

5. Waveforms are taken receiving color bar signal with enough sensitivity.

6. Voltage reading shown are nominal values and may vary ±20 % except H.V.