Toshiba 42WLT66 User 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
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
p
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
p
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
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.
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
p
roduct made with lea
d
-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
p
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.
WARNING: This product is manufactured using lead free solder.
DO NOT USE LEAD BASED SOLDER TO REPAIR THIS PRODUCT!

SAFETY INSTRUCTION
Safety Precaution
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.
WARNING: BEFORE SERVICING THIS CHASSIS, READ THE "SAFETY
PRECAUTION" AND "PRODUCT SAFETY NOTICE" INSTRUCTIONS BELOW.
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.

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.)
zPlug the AC cord directly into the AC outlet. Do NOT use an isolation transformer
for this check.
zConnect 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

zThe potential at any point (TOUCH CURRENT) expressed as voltage and
does not exceed the following value:
Resistance values in orms (Ω).
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).
V: Voltmeter or oscilloscope
(r.m.s. or peak reading)
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);

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.
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.
- for d.c. : = 1.0 V

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

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.