Saturday 21 March 2020

REPAIR / SERVICING TV BBK LT4005S

Technical description and composition of the BBK LT4005S TV, panel type and applicable modules. The composition of the modules.
BBK
Model: LT4005S
Chassis / Version: 200-100-GF328-FH
Panel: LTA400WT-L11
Inverter (backlight): integrated into PSU
Power Supply (PSU): TRIDENT
PWM Power: PWM SOT23-6
MainBoard: 200-100-GF328-FH // 200-107-JK371XP-CH REV: C
IC MainBoard: SPI FLASH: A29040, EEPROM 24C64, SAA7117H, M30620SPGP, SiI9011CLU
Tuner: M09WPP-2P-E
Technical specifications LT4005S
BBK LT4005S
General recommendations for repairing TV LCD
Possible malfunctions
- The BBK LT4005S TV does not turn on and does not show any signs of turning on, it does not respond to the control buttons or to the remote control.
Often in such cases, the TRIDENT power module is faulty. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches and rectifier diodes of the converters for a probable short circuit.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM) PWM SOT23-6, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or the inverter.After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, you must ring in its converter power keys for breakdown and secondary windings of transformers for an open.
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 TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 200-100-GF328-FH 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing SPI FLASH elements: A29040, EEPROM 24C64, SAA7117H, M30620SPGP, SiI9011CLU requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
Before changing the M09WPP-2P-E tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Owners and users of the BBK LT4005S 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!

FIRMWARE FOR SPI FLASH, EEPROM -------------> BBK LT4005S, Main: 200-100-GF328-FH // 200-107-JK371XP-CH REV:C , Panel: LTA400WT-L11


schematic diagram ------------->  LT4005S TRIDENT Power supply




The appearance of the MainBoard 200-100-GF328-FH is shown in the figure below:
200-100-GF328-FH
200-100-GF328-FH can be used in TVs:
BBK LT3709 (Panel T370XW01 rev. 0), BBK LT4005S (Panel LTA400WT-L11).
Key Features of BBK LT4005S:
Installed matrix (LCD-panel) LTA400WT-L11.
To power the backlight, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the BBK LT4005S TV are generated by the TRIDENT power module or its analogs using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a 200-100-GF328-FH module using SPI FLASH chips: A29040, EEPROM 24C64, SAA7117H, M30620SPGP, SiI9011CLU and others.
The M09WPP-2P-E tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTA400WT-L11
Type: a-Si TFT-LCD, Panel
Diagonal size: 40 inch
Resolution: 1366x768, WXGA
Display Mode: S-PVA, Normally Black, Transmissive
Active Area: 885.168x497.664 mm
Surface: Antiglare (Haze 44%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1200: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 10/6 (Tr / Td); 8 (G to G)
Frequency: 60Hz
Lamp Type: 18 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V


BBK LT4005S LCD TV with LTA400WT-L11 LCD, 40 "(102 cm) diagonal display in 16: 9 format. 500 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Maximum brightness to minimum ratio (contrast) ) is 1200: 1. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in stand mouths 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the sound speaker system 20 W (2x10 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV x2, audio x5, component, SCART x2, RGB, VGA, HDMI x2. 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, 1280x1024, 1360x768.
The power consumed by the TV in the operating mode from the network is 300 watts.
Overall dimensions: 985x754x270 mm.
TV Weight: 28.5 kg.
Attention! The BBA LT4005S's LTA400WT-L11 LCD TV panel is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!