Technical description and composition of the BBK LT1900S TV, panel type and applicable modules. The composition of the modules.BBK
Model: LT1900S
Chassis / Version: 21903-3
Panel: M190A1-L02 Rev. C1
Inverter (backlight): 5INV403-1 20070125
PWM Inverter: MP1008ES (16H) PL
MOSFET Inverter: BA642B chip
Power Supply (PSU): Adapter AK083 (5AK083-1) 12V 4.5A 54W
PWM Power: TOP249YN
Mainboard: 21903-3
IC MainBoard: Cpu: MST718BU-LF, Spi Flash: PM25LV020, 24C32
Tuner: JS-6H2 / T121
Control: LT117-02
Technical specifications LT1900S
BBK LT1900S
General recommendations for repairing TV LCD
Possible malfunctions
- The BBK LT1900S TV does not turn on and does not show any signs of turning on. There are no reactions to the control buttons or the remote control.
Most likely in this case, the main switching power supply (IPS) Adapter is faulty.
This TV model is equipped with an external power adapter adapter AK083 (5AK083-1) 12V 4.5A 54W, 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 characteristic of IIP. 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) TOP249YN. It is checked only by replacement with a known good one.
- 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.
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.
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 during work, 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, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the 21903-3 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). 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 Cpu chips: MST718BU-LF, Spi Flash: PM25LV020, 24C32 and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
Before replacing the JS-6H2 / T121 tuner, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Attention! Users and owners of LT1900S TVs who do not have the appropriate qualifications, knowledge and experience are strongly advised against self-repair attempts in order to avoid negative consequences that could lead to the complete non-repairability of the device.
SCHEMATIC / MANUAL -------------> BBK LT1500S-2, LT1500S-3, LD1506SI-2, LD1506SI-3, LT1900S, LD1906SI, LT2000S, LD2006SI-2
Key Features of BBK LT1900S:
Installed matrix (LCD panel) M190A1-L02 Rev. C1.
To power the backlight, an inverter 5INV403-1 is used, it is controlled by the PWM controller MP1008ES (16n), pl. As power elements of the inverter, keys of type BA642B chip are used.
To power all the internal components of the BBK LT1900S TV, an external adapter type AK083 (5AK083-1) 12V 4.5A 54W is used using TOP249YN chips.
MainBoard - the main board (motherboard) is a 21903-3 module, using Cpu microcircuits: MST718BU-LF, Spi Flash: PM25LV020, 24C32 and others.
The tuner JS-6H2 / T121 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CMO
Model: M190A1-L02
Type: a-Si TFT-LCD, Panel
Diagonal size: 19.0 inch
Resolution: 1440x900, WXGA +
Display Mode: TN, Normally White, Transmissive
Active Area: 410.4x256.5 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 850: 1
Display Colors: 16.2M (6-bit + FRC)
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V
Installed matrix (LCD panel) M190A1-L02 Rev. C1.
To power the backlight, an inverter 5INV403-1 is used, it is controlled by the PWM controller MP1008ES (16n), pl. As power elements of the inverter, keys of type BA642B chip are used.
To power all the internal components of the BBK LT1900S TV, an external adapter type AK083 (5AK083-1) 12V 4.5A 54W is used using TOP249YN chips.
MainBoard - the main board (motherboard) is a 21903-3 module, using Cpu microcircuits: MST718BU-LF, Spi Flash: PM25LV020, 24C32 and others.
The tuner JS-6H2 / T121 provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: CMO
Model: M190A1-L02
Type: a-Si TFT-LCD, Panel
Diagonal size: 19.0 inch
Resolution: 1440x900, WXGA +
Display Mode: TN, Normally White, Transmissive
Active Area: 410.4x256.5 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 850: 1
Display Colors: 16.2M (6-bit + FRC)
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (2 ch, 8-bit), 30 pins
Voltage: 5.0V
BBK LT1900S LCD TV with M190A1-L02 LCD display, 19 "(48 cm) diagonal 16:10 aspect ratio. 300 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Maximum brightness to minimum ratio (contrast) ) is 700: 1. The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i.
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, audio x2, component, SCART, RGB, VGA. 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 the operating mode from the network is 65 watts.
Overall dimensions: With stand 813x642x240 mm, Without stand 498x371x83 mm.
Attention! The BBK LT1900S LCD TV M190A1-L02 Rev. C1 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!
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, audio x2, component, SCART, RGB, VGA. 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 the operating mode from the network is 65 watts.
Overall dimensions: With stand 813x642x240 mm, Without stand 498x371x83 mm.
Attention! The BBK LT1900S LCD TV M190A1-L02 Rev. C1 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!