Technical description and composition of the BBK LT1920S TV, panel type and applicable modules. The composition of the modules.BBK
Model: LT1920S
Chassis / Version: CV078H
Panel: MT190AW01 V.C
Inverter (backlight): 7575 + TL494
PWM Inverter: TL494C (16)
MOSFET Inverter: AO4606 (08)
Power Supply (PSU): 7575 + TL494
PWM Power: LD7573PS (8)
MainBoard: CVO78H 901H0008 E
IC MainBoard: MST3383AMCK-LF-170 A3MD549999C TDA1517P MSP 341SG B8 V3 CS24C02MO
Tuner: TSN3311 - Q
Technical specifications LT1920S
BBK LT1920S
General recommendations for repairing TV LCD
Possible manifestations of defects
- The BBK LT1920S TV does not turn on and does not show any signs of operability at all. There is no reaction to either the remote control or the front panel control buttons.
Failure in such cases should be sought in the power supply circuits 7575 + TL494. 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 main 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 key may be PWM (PWM) LD7573PS (8). 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 supply module, or by inverter defects, as well as by 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, it is necessary to disable the inverter protection. 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 CVO78H 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). Sometimes it is necessary to check or replace (if necessary) the elements of the MainBoard board - MST3383AMCK-LF-170 A3MD549999C TDA1517P MSP 341SG B8 V3 CS24C02MO. In cases where the BGA processor is used, its malfunction is usually detected by local heating.
If a TSN3311 - Q tuner is suspected of malfunction, first of all, it is necessary to verify the correctness of the software, as well as the presence of the necessary supply voltage levels and data exchange pulses with the processor via the I2C bus at the corresponding tuner pins.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
Service Manual with Schematic Diagram 33 pages of 2008 on the LH1906TSA, LH1906TSA, LH2206TSA, LT1920S, LT2220S.
Main features of the BBK LT1920S device:
Installed matrix (LCD panel) MT190AW01 V.C.
To power the backlight, an inverter 7575 + TL494 is used, it is controlled by a TL494C PWM controller (16). As power elements of the inverter, keys of the type AO4606 (08) are used.
The necessary supply voltages for all nodes of the BBK LT1920S TV are generated by the 7575 + TL494 power supply module or its analogs using LD7573PS microcircuits (8).
MainBoard - the main board (motherboard) is a CVO78H module, using chips MST3383AMCK-LF-170 A3MD549999C TDA1517P MSP 341SG B8 V3 CS24C02MO and others.
The tuner TSN3311 - Q allows you to receive television programs and tune to channels.
Additional technical information about the panel:
Brand: INNOLUX
Model: MT190AW01 V.C
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: 250 cd / m²
Contrast Ratio: 1000: 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 LT1920S LCD TV with MT190AW01 LCD, 19 "(48 cm) diagonal 16:10 aspect ratio. 300 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 1000: 1. It is possible to view images in high quality HD at a resolution of 1440x900 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i.
The power of the speaker system is 3 watts. 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, S-Video, SCART, RGB, VGA, HDMI. 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 60 watts.
Overall dimensions: With stand 788x561x252 mm, Without stand 788x511x101 mm.
Attention! The BBK LT1920S MT190AW01 V.C 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!