Technical description and composition of the BBK LT2000S TV, panel type and applicable modules. The composition of the modules.BBK
Model: LT2000S
Chassis / Version: 21903-7
Panel: A201SN02
Inverter (backlight): 6 Lamp
PWM Inverter: MP1048
MOSFET Inverter: AO4822
Power Supply (PSU): Adapter 12V
MainBoard: 21903-7 AAV5V2.05
IC MainBoard: CPU: MST718BE-LF, 24C32, Pm25LV020
Tuner: JS-6H2 / T121
Technical specifications LT2000S
BBK LT2000S
General recommendations for repairing TV LCD
Possible manifestations of defects
- BBK LT2000S does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
Failure in such cases should begin to look in the adapter power supply circuits.
This model of TV is equipped with an external power adapter adapter type 12V, which the owner can purchase independently, and repairing it may not always be advisable, however, sometimes it makes sense to open it and eliminate simple typical defects typical of IPS. It is necessary to measure its output voltages, and in case of their absence, check the operability of the power switches of the converters and rectifier diodes for the probability of a short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often 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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
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 inverter. If all the electrolytic capacitors of the filter according to the power supply of the inverter are working, make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
If in diagnosing a malfunction, it is necessary to disable the inverter protection, there is a risk of failure of the power elements of the inverter, and special care is required when working, and after they are finished, it is necessary to restore the protection circuits for further safe operation of the TV by the owner in normal mode.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 21903-7 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the CPU elements: MST718BE-LF, 24C32, Pm25LV020. BGA chip malfunctions are usually easy to detect by warming up.
If the TV works normally from external devices, but does not tune into television channels, the tuner JS-6H2 / T121 may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
It should be remembered! Attempts to independently repair the BBK LT2000S TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
FIRMWARE FOR SPI FLASH --------------> BBK LT2000S, Main: AAV5V2.05, Panel: A201SN02
Service Manual / Schematic Diagram ------------------> BBK LT2000S Chassis 21903-7
BBK LD2006SI, LD1506SI, LT1500S, LT2000S, LD1906S, LT1900S.
Service Manual with Schematic Diagram 168 pages 2006 on model LD2006SI-2, LD1506SI-2, LD1506SI-3, LT1500S-2, LT1500S-3, LT2000S, LD1906SI, LT1900S.
The appearance of MainBoard 21903-7 is shown in the figure below:21903-7
21903-7 can be used in TVs:
BBK LD1906SI (Panel SVA190WX02TB), BBK LT2000S (Panel A201SN02).
Key Features of BBK LT2000S:
Installed matrix (LCD panel) A201SN02.
Inverter 6 is used to power the backlight, controlled by the MP1048 PWM controller. As power elements of the inverter, keys of the type AO4822 are used.
To power all the internal components of the BBK LT2000S TV, an external adapter 12V type is used.
MainBoard - the main board (motherboard) is a module 21903-7, using CPU chips: MST718BE-LF, 24C32, Pm25LV020 and others.
The tuner JS-6H2 / T121 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: AUO
Model: A201SN02 V5
Type: a-Si TFT-LCD, Panel
Diagonal size: 20.1 inch
Resolution: 800x600, SVGA
Display Mode: TN, Normally White, Transmissive
Active Area: 408x306 mm
Surface: Antiglare
Brightness: 450 cd / m²
Contrast Ratio: 700: 1
Display Colors: 16.2M (6-bit + FRC), CIE1931 72%
Response Time: 11/5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 6 pcs CCFL Without Driver
Signal Interface: TTL (1 ch, 8-bit), 50 pins
Voltage: 5.0V
BBK LT2000S LCD TV with A201SN02 LCD, diagonal size 20 ", 4: 3 aspect ratio. The brightness of the screen is 450 cd / m² with CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 800: 1. The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation takes place in the standards 480i, 480p, 576i.
The power of the acoustic system of sound 6 W (2x3W) provide two 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, component, SCART, RGB. An output for connecting headphones is provided.
The power consumed by the TV in the operating mode from the network is 60 watts.
Overall dimensions: 620x450x202 mm.
TV Weight: 7.55 kg.
Attention! The BBK LT2000S LCD TV panel A201SN02 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!