Hisense 50E77HQ User manual

LCDTelevision
Service Manual
Chassis：MT9900
Version: V 1.0
Hisense Visual Technology Co.，Ltd.
November 19, 2021

- 2 -
REVISION HISTORY
Version
Revise content
Reviser
Date
V1.00
First issued
Wangyue
2021-11-19

- 3 -
Contents
Contents.......................................................................................................................................................................- 3 -
Service Manual ...........................................................................................................................................................- 4 -
1. Precautions and notices.....................................................................................................................................- 4 -
1.1 Warning...................................................................................................................................................- 5 -
1.2 Notes.......................................................................................................................................................- 7 -
2. TV boards:......................................................................................................................................................- 10 -
2.1 Main board layout.................................................................................................................................- 10 -
2.2 TV boards part list ................................................................................................................................- 16 -
3. Factory/Service OSD Menu andAdjustment..................................................................................................- 17 -
3.1 Remote Control.....................................................................................................................................- 17 -
3.2 Factory OSD Menu...............................................................................................................................- 19 -
4. Software Upgrading........................................................................................................................................- 24 -
4.1 USB Upgrade........................................................................................................................................- 24 -
4.2 Flash Tool upgrading ............................................................................................................................- 26 -
5. Trouble shooting.............................................................................................................................................- 29 -
5.1 Troubleshooting for Remote Control....................................................................................................- 29 -
5.2 Troubleshooting for Function Key........................................................................................................- 30 -
5.3 TV won’t Power On..............................................................................................................................- 31 -
5.4 Troubleshooting for Audio....................................................................................................................- 32 -
5.5 Troubleshooting for TV/VGA/HDMI input..........................................................................................- 33 -
5.6 Troubleshooting for YPbPr input..........................................................................................................- 34 -
5.7 Troubleshooting for Video input...........................................................................................................- 35 -
6. Signals Block Diagram & power assign & schematic diagram......................................................................- 36 -

- 4 -
Service Manual
1. Precautions and notices
BEFORE SERVICING THE LCD TV, READ THE SAFETY PRECAUTIONS IN
THIS MANUAL.
USE ONLY MANUFACTURER SPECIFIED REPLACEMENT PARTS WHEN
SERVICING.
USE OF NON-AUTHORIZED PARTS WILL VOID THE MANUFACTURE'S
WARRANTY
Proper service and repair is important to the safe, reliable operation of all Hisense
Equipment. The service procedures recommended by Hisense and described in this
Service Guide are effective methods of performing service operations. Some of these
service operations require the use of tools specially designed for the purpose. The special
tools should be used when and as recommended.
It is important to note that this manual contains various CAUTIONS and NOTICES
which should be carefully read in order to minimize the risk of personal injury to service
personnel. The possibility exists that improper service methods may damage the
equipment and pose risk of personal injury
. It is also important to understand that these CAUTIONS and NOTICES ARE NOT
EXHAUSTIVE. Service should only be performed by an experienced electronics

- 5 -
technician trained in the proper Television safety and service methods and procedures
Hereafter throughout this manual.
1.1 Warning
1.1.1
Critical components having special safety characteristics are identified with a by the
Ref. No. in the parts list. Use of non-manufacturer's recommended parts may create
shock, fire, or other hazards. Under no circumstances should the original design be
modified or altered without written permission from RCA. Hisense assumes no liability,
express or implied, arising out of any unauthorized modification of design. Service tech
assumes all liability.
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, be sure to
use anti-static table mats and properly use a grounding wrist stra. Keep components and
tools also at this same potential.
IMPORTANT:
Always disconnect the power cord from AC outlet before replacing parts or modules.
1.1.3
To prevent electrical shock, use only a properly grounded 3 prong outlet or extension
cord.

- 6 -
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 and will void the
manufacturer's warranty.
1.1.5
Safety regulations require that after a repair the set must be returned in its original
condition. In addition, prior to closing set, check that:
-Note:
>All wire harnesses and flex cables are properly routed and secured with factory tape
and/or mounted cable clamps.
> All cables and connectors are properly insulated and do not have any bare wires/lead
exposed
1.1.6
(1) Do not supply a voltage higher than that specified to this product. This may
damage the product and may cause a fire.
(2) Do not use this product:
> High humidity areas
> In an area where any water could enter or splash into the unit.
High humidity and water could damage the product and cause fire.

- 7 -
(3) 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.
(4) 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.
(5) Do not pull out or insert the power cable from/to an outlet with wet hands. It may
cause electric shock.
(6) Do not damage or modify the power cable. It may cause fire or electric shock.
(7) 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.
(8) 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.
(9) 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.

- 8 -
• 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
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
may trip the main 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.
• 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

- 9 -
problems resulting from scratches on the parts, the deformation of parts, and
short-circuits due to residual electric charge.
• 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
service personnel to important safety information in the service literature. .

- 10 -
2. TV boards:
2.1 Main board layout
2.1.1 The top of main board (2RSAG7.820.11711)
The rear of main board (2RSAG7.820.11711)