Technical description and composition of the BBK LT4221HD TV, panel type and applicable modules. The composition of the modules.BBK
Model: LT4221HD
Chassis / Version: Ver1
Panel: LCD42W60P
Power Supply (PSU): RSAG7.820.1185 VER.E TU25C74-1
MainBoard: LCD42W60P
Tuner: TDQ-6FT
Technical Specifications LT4221HDU
BBK LT4221HD
General recommendations for repairing TV LCD
Possible manifestations of defects
- The BBK LT4221HD 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.
With such manifestations, a malfunction is most likely to be detected in the RSAG7.820.1185 power supply module. It is necessary to measure the secondary output voltage, 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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. The PWM chip can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, but there is sound and reaction to commands from the remote control. Or the image appears immediately after turning on and 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.
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 indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the LCD42W60P 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).
If a TDQ-6FT 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 on the corresponding tuner pins.
Attention! Users and owners of LT4221HD 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 complete non-repairability of the device.
Service Manual with Schematic Diagram 54 pages of 2008 on the LT4217HD, LT4219HD, LT4221HD, LT4221HDU
Main features of the BBK LT4221HD device:
Installed matrix (LCD panel) LCD42W60P.
The formation of the necessary supply voltages for all nodes of the BBK LT4221HD TV is carried out by the RSAG7.820.1185 power module, or its analogs.
MainBoard - the main board (motherboard) is an LCD42W60P module.
The TDQ-6FT tuner provides TV reception and channel tuning.
BBK LT4221HDU LCD TV with 42 "(106 cm) diagonal LCD display in 16: 9 format. 400 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 800 : 1. The design and technical capabilities of the TV provide for viewing broadcasts and films in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD). The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC. elaboration and shaping of the digital signal occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p.
The power of the sound speaker system is 14 W (2x7 W). 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 x4, S-Video, component x2, SCART x2, RGB, VGA, HDMI x2, USB. 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 250 watts.
Overall dimensions: 1028x736x310 mm.
The mass of the TV: 27 kg.
Attention! The BBK LT4221HDU 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!