BBK LT2619SU User manual

Service Manual
LT2619SU/LT2621SU

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LCD TV Service Manual
Contents
Contents................................................................................................................................................................- 2 -
Service Manual ....................................................................................................................................................- 3 -
1. Precautions and notices..............................................................................................................................- 3 -
1.1 WARNING ......................................................................................................................................- 4 -
1.2 NOTES ............................................................................................................................................- 7 -
2. Product Function Specifications..............................................................................................................- 10 -
2.1 Product Function............................................................................................................................- 10 -
2.2 Specifications.................................................................................................................................- 12 -
3. LCD Panel Spec.......................................................................................................................................- 13 -
3.1 General Description.......................................................................................................................- 13 -
3.2 General Features............................................................................................................................- 13 -
4. Chassis Layout and Overall Wiring Diagrams ........................................................................................- 14 -
4.1 Chassis Layout...............................................................................................................................- 14 -
4.2 Wires and Cables Overall Wiring Diagrams .................................................................................- 15 -
5. Factory/Service OSD Menu and Adjustment...........................................................................................- 16 -
5.1 To enter the Factory OSD Menu....................................................................................................- 16 -
5.2 Factory OSD Menu........................................................................................................................- 16 -
6. Software Upgrading.................................................................................................................................- 20 -
6.1 Get ready for upgrading.................................................................................................................- 20 -
6.2 Upgrading with the ISP_TOOL4.0.9.............................................................................................- 29 -
7. Troubleshooting.......................................................................................................................................- 34 -
7.1 Troubleshooting for Remote Control.............................................................................................- 34 -
7.2 Troubleshooting for Function Key.................................................................................................- 35 -
7.3 TV won’t Power On.......................................................................................................................- 36 -
7.4 Troubleshooting for Audio.............................................................................................................- 37 -
7.5 Troubleshooting for TV/VGA/HDMI input...................................................................................- 38 -
7.6 Troubleshooting for YPbPr input...................................................................................................- 39 -
7.7 Troubleshooting for Video/S-Video/ SCART input.......................................................................- 40 -
8. Explode View...........................................................................................................................................- 41 -
9. Schematic circuit diagram .......................................................................................................................- 41 -

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LCD TV Service Manual
Service Manual
1. Precautions and notices
BEFORE SERVICING THE LCD TV, READ THE SAFETY PRECAUTIONS IN
THIS MANUAL.
WHEN REPLACEMENT PARTS ARE REQUIRED, BE SURE TO USE
REPLACEMENT PARTS SPECIFIED BY THE MANUFACTURER.

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LCD TV Service Manual
not undertaken any such broad evaluation. Accordingly, a serviceman that uses a
service procedure or tools, which are not recommended by Hisense, must first satisfy
himself thoroughly that neither his safety nor the safe of the equipment will be
jeopardized by the service method selected.
1.1 WARNING
1.1.1
DANGERCAUTION CAUTION
TO ENSURE THE CONTINUED RELIABILITY OF THIS PRODUCT, USE ONLY
ORIGINAL MANUFACTURER'S REPLACEMENT PARTS, WHICH ARE LISTED WITH
THEIR PART NUMBERS IN THE PARTS LIST SECTION OF THIS SERVICE GUIDE.

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LCD TV Service Manual
1.1.2.
All ICs and many other semiconductors are susceptible to electrostatic discharges
(ESD). Careless handling during repair can reduce life drastically. When repairing,
make sure that you are connected with the same potential as the mass of the set by a
wristband with resistance. Keep components and tools also at this same potential.
1. Never replace modules or other components while the unit is switched on.
2. When making settings, use plastic rather than metal tools. This will prevent
any short circuits and the danger of a circuit becoming unstable.
1.1.3
To prevent electrical shock, do not use this polarized ac plug with an extension cord,
receptacle, or the outlet unless the blades can be fully inserted to prevent blade
exposure.
To prevent electrical shock, match wide blade or plug to wide slot, fully insert.
1.1.4
When replacement parts are required, be sure to use replacement parts specified by
the manufacturer or have the same characteristics as the original part. Unauthorized
substitutions may result in fire, electric shock, or other hazards.
1.1.5
Safety regulations require that after a repair the set must be returned in its original
condition. In particular attention should be paid to the following points.
-Note: The wire trees should be routed correctly and fixed with the mounted

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LCD TV Service Manual
cable clamps.
-The insulation of the mains lead should be checked for external damage.
1.1.6
(1) Do not touch Signal and Power Connector while this product operates. Do not
touch EMI ground part and Heat Sink of Film Filter.
(2) Do not supply a voltage higher than that specified to this product. This may
damage the product and may cause a fire.
(3) Do not use this product in locations where the humidity is extremely high,
where it may be splashed with water, or where flammable materials surround it. Do
not install or use the product in a location that does no satisfy the specified
environmental conditions. This may damage the product and may cause a fire.
(4) If a foreign substance (such as water, metal, or liquid) gets inside the panel
module, immediately turn off the power. Continuing to use the product may cause
fire or electric shock.
(5) If the product emits smoke, and abnormal smell, or makes an abnormal sound,
immediately turn off the power. Continuing to use the product, it may cause fire or
electric shock.
(6) Do not disconnect or connect the connector while power to the product is on. It
takes some time for the voltage to drop to a sufficiently low level after the power
has been turned off. Confirm that the voltage has dropped to a safe level before
disconnecting or connecting the connector.

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LCD TV Service Manual
(7) Do not pull out or insert the power cable from/to an outlet with wet hands. It
may cause electric shock.
(8) Do not damage or modify the power cable. It may cause fire or electric shock.
(9) If the power cable is damaged, or if the connector is loose, do not use the
product: otherwise, this can lead to fire or electric shock.
(10) If the power connector or the connector of the power cable becomes dirty or
dusty, wipe it with a dry cloth. Otherwise, this can lead to fire.
(11) Use only with the cart, stand, tripod, bracket, or table specified by the
manufacturer, or sold with the apparatus. When a cart is used, use caution when
moving the cart/apparatus combination to avoid injury from tip-over.
1.2 NOTES
Notes on Safe Handling of the LCD panel and during service
The work procedures shown with the Note indication are important for ensuring the
safety of the product and the servicing work. Be sure to follow these instructions.
• Before starting the work, secure a sufficient working space.
• At all times other than when adjusting and checking the product, be sure to turn
OFF the POWER Button and disconnect the power cable from the power source of
the TV during servicing.
• To prevent electric shock and breakage of PC board, start the servicing work at least
30 seconds after the main power has been turned off. Especially when installing and
removing the power board, start servicing at least 2 minutes after the main power has

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LCD TV Service Manual
been turned off.
• While the main power is on, do not touch any parts or circuits other than the ones
specified. If any connection other than the one specified is made between the
measuring equipment and the high voltage power supply block, it can result in
electric shock or activation of the leakage-detection circuit breaker.
• When installing the LCD module in, and removing it from the packing carton, be
sure to have at least two persons perform the work.
• When the surface of the panel comes into contact with the cushioning materials, be
sure to confirm that there is no foreign matter on top of the cushioning materials
before the surface of the panel comes into contact with the cushioning materials.
Failure to observe this precaution may result in, the surface of the panel being
scratched by foreign matter.
• When handling the circuit board, be sure to remove static electricity from your body
before handling the circuit board.
• Be sure to handle the circuit board by holding the large parts as the heat sink or
transformer. Failure to observe this precaution may result in the occurrence of an
abnormality in the soldered areas.
• Do not stack the circuit boards. Failure to observe this precaution may result in
problems resulting from scratches on the parts, the deformation of parts, and
short-circuits due to residual electric charge.
• Routing of the wires and fixing them in position must be done in accordance with

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LCD TV Service Manual
the original routing and fixing configuration when servicing is completed. All the
wires are routed far away from the areas that become hot (such as the heat sink).
These wires are fixed in position with the wire clamps so that the wires do not move,
thereby ensuring that they are not damaged and their materials do not deteriorate over
long periods of time. Therefore, route the cables and fix the cables to the original
position and states using the wire clamps.
• Perform a safety check when servicing is completed. Verify that the peripherals of
the serviced points have not undergone any deterioration during servicing. Also
verify that the screws, parts and cables removed for servicing purposes have all been
returned to their proper locations in accordance with the original setup.
The lightning flash with arrowhead symbol, within an equilateral
triangle is intended to alert the user to the presence of uninsulated
dangerous voltage within the products enclosure that may be of sufficient magnitude
to constitute a risk of electric shock.
The exclamation point within an equilateral triangle is intended to
alert the user to the presence of important operating and maintenance
(servicing) instructions in the literature accompanying the set.

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LCD TV Service Manual
2. Product Function Specifications
2.1 Product Function