Saturday 21 March 2020

REPAIR / SERVICING TV BBK LT3710HD

Technical description and composition of the BBK LT3710HD TV, panel type and applicable modules. The composition of the modules.
BBK
Model: LT3710HD
Chassis / Version: 569HK1501C
Panel: T370HW02 v.4
T-CON: T370HW02 V402, W9864G2GH-7
Inverter (backlight): VIT71037.50
PWM Inverter: OZ9643N, Z2675D, ZHP805
Power Supply (PSU): 569FT0120D
MainBoard: 569HK1501C
IC MainBoard: 24LC64I, MST9E89DL-LF A7ME377C, HY5DU281622FTP-4, flash 80A7
Tuner: TDQ-6F / W124XC
Control: RC-3704
Technical Specifications LT3710HD
BBK LT3710HD
General recommendations for repairing TV LCD
Possible malfunctions
- BBK LT3710HD TV does not turn on at all. There is no reaction to the remote control or to the control buttons from the front panel. Indicator lights do not light or flash.
Most likely in this case, the main switching power supply (IPS) 569FT0120D is faulty. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the elements of the primary circuit, the mains fuse usually breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM). It is checked only by replacement with a known good one.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
These manifestations can be triggered by a power module, or by defects in the inverter, as well as a distortion of the currents in the lamps due to their uneven wear. If all the electrolytic capacitors of the filter according to the inverter power supply are serviceable, you should make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
Sometimes, for diagnostic purposes, inverter protection must be disabled. In such cases, special care must be taken during work, and the protection circuits should be restored immediately after the repair is completed.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the 569HK1501C motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its chips 24LC64I, MST9E89DL-LF A7ME377C, HY5DU281622FTP-4, flash 80A7 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
The TDQ-6F / W124XC tuner malfunction is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Owners and users of the BBK LT3710HD TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!


The appearance of the MainBoard 569HK1501C is shown in the figure below:
569HK1501C
The appearance of the power supply
Main features of the BBK LT3710HD device:
Installed matrix (LCD-panel) T370HW02 v.4.
The matrix control uses the Timing Controller (T-CON) T370HW02.
To power the backlight, an inverter VIT71037.50 is used, it is controlled by the PWM controller OZ9643N, Z2675D, ZHP805.
The necessary supply voltages are generated for all nodes of the BBK LT3710HD TV by the 569FT0120D power module or its analogs.
MainBoard - the main board (motherboard) is a 569HK1501C module, using 24LC64I, MST9E89DL-LF A7ME377C, HY5DU281622FTP-4, flash 80A7 and others chips.
The TDQ-6F / W124XC tuner provides TV reception and channel tuning.
Information from an alternative source:
BBK LT3710HD
Panel Type (Matrix): T370HW02 v.4,
Motherboard: 569HK1501C, 24LC64I, MST9E89DL-LF A7ME377C, HY5DU281622FTP-4, flash 80A7, Tuner: TDQ-6F / W124XC,
T-con: T370HW02 V402, W9864G2GH-7 x2
Invertor: VIT71037.50, OZ9643N, Z2675D, ZHP805
PSU: 569FT0120D
Remote control: RC-3704 BBK lt3710s
Additional technical information about the panel:
Brand: AUO
Model: T370HW02 V4
Type: a-Si TFT-LCD, Panel
Diagonal size: 37 inch
Resolution: 1920x1080, FHD
Display Mode: AMVA, Normally Black, Transmissive
Active Area: 819.36x460.89 mm
Surface: Antiglare (Haze 11%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 2500: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: CCFL Embedded (Inverter)
Signal Interface: LVDS (2 ch, 8-bit), 51 pins
Voltage: 12.0V


Brand: BBK, Model: LT3710HD.
Briefly from the TV: LCD, 1080p Full HD, diagonal 37 "(94 cm), HDMI: 3.
The composition uses MainBoard 569HK1501C and an LCD panel (matrix) T370HW02 v.4.
Power Supply Unit (PSU) 569FT0120D Power Supply.
BBK LT3710HD LCD TV with T370HW02 LCD, 37 "(94 cm) diagonal display in 16: 9 format. 500 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 1500: 1. The design and technical capabilities of the TV provide viewing of broadcasts and films in high quality HD with a resolution of 1920x1080 pixels in graphic decomposition according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic Digital signal processing and generation takes place in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Stereo sound is realized by two built-in speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x3, S-Video, component, SCART x2, RGB, VGA, HDMI x3. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768.
The power consumed by the TV in operation from the network is 230 watts.
Overall dimensions: 955x719x300 mm.
TV Weight: 25 kg.
Attention! The T370HW02 v.4 LCD panel of the BBK LT3710HD is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!