Saturday 21 March 2020

REPAIR / SERVICING TV BBK LT3219S

Technical description and composition of the BBK LT3219S TV, panel type and applicable modules. The composition of the modules.
BBK
Model: LT3219S
Chassis / Version: RSAG7.820.1269
Panel: V315B1-L01 Rev. C2
T-CON: V315B1-C01; CM2681A-KQ, EM63615TS-7G, AS15-G
Inverter (backlight): I315B1-16A
PWM Inverter: OZ964GN
MOSFET Inverter: AO4614A
Power Supply (PSU): RSAG7.820.1032 / ROH
PWM Power: NCP1207A
MainBoard: RSAG7.820.1269 ROH VER.C
IC MainBoard: MST9E19B-LF, TDA7266SA, CM1671-KQ, A25L40PUO, AZ4558CM, TDA9886TS, P15V330SQE, AP1520
Tuner: TDQ-6FT / W126H / ROH
Technical Specifications LT3219SU
BBK LT3219S
General recommendations for repairing TV LCD
Possible manifestations of defects
- BBK LT3219S does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
With such manifestations, in most cases, the RSAG7.820.1032 power module is faulty. It is necessary to measure its output voltages and, if they are absent, to check the short circuit probability in the converters power switches and rectifier diodes.
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 (NWP1207A). 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.
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.
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 RSAG7.820.1269 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits 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 elements MST9E19B-LF, TDA7266SA, CM1671-KQ, A25L40PUO, AZ4558CM, TDA9886TS, P15V330SQE, AP1520 requires the necessary training and professional skills in repairing modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
The TDQ-6FT / W126H / ROH tuner malfunction is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
Once again, remind users! Attempts to repair the TV BBK LT3219S on its own without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
One of the typical defects of the BBK LT3219S TV can occur in the V315B1-L01 Rev.C2 panel.
External manifestations: color distortion in the image as a negative in the image, light tones predominate. Typically, in such cases, the AS15-G gamma corrector is faulty. Another indicator of its malfunction is an excessively strong heating, which in practice allows you to do without measuring the voltage gradations of gray.
In most cases, replacing the AS15-G solves the problem.
It should be remembered that similar symptoms can cause faults in the column drivers of the panel, which is usually indicated by interference in the form of even vertical stripes on the screen. Then, after replacing the AS15-G, the situation does not change. Drivers are in loops and cannot be replaced. In this case, it is necessary to replace the glass panel.


schematic diagram -------------> I315B1-16A I315B1-16A Invertor Schematic

 The appearance of the MainBoard RSAG7.820.1269 is shown in the figure below:
RSAG7.820.1269
RSAG7.820.1269 can be used in TVs:
BBK LT2617S (Panel V260B1-L02 rev.c1), BBK LT2621S (Panel V260B1-L02), BBK LT3221S (Panel V315B1-L01 Rev.C2), BBK LT3217S (Panel AX080D002F), BBK LT3219S (Panel V315B1-L01 Rev.C2).
The appearance of the power supply
Main features of the BBK LT3219S device:
Installed matrix (LCD panel) V315B1-L01 Rev. C2.
The matrix control uses the Timing Controller (T-CON) V315B1-C01 ;.
To power the backlight used inverter I315B1-16A, controlled by the PWM controller OZ964GN. As power elements of the inverter, keys of the type AO4614A are used.
The necessary supply voltages for all nodes of the BBK LT3219S TV are generated by the RSAG7.820.1032 power module or its analogs using NCP1207A microcircuits.
MainBoard - the main board (motherboard) is an RSAG7.820.1269 module, using microchips MST9E19B-LF, TDA7266SA, CM1671-KQ, A25L40PUO, AZ4558CM, TDA9886TS, P15V330SQE, AP1520 and others.
The TDQ-6FT / W126H / ROH tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: CMO
Model: V315B1-L01
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: Super MVA, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 500 cd / m²
Contrast Ratio: 1500: 1
Display Colors: 16.7M (8-bit), CIE1931 72%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: 16 pcs CCFL Embedded (Inverter)
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V
 
BBK LT3219SU LCD TV with 32 "(81 cm) diagonal LCD display in 16: 9 format. The brightness of the screen is 500 cd / m² by CCFL (EEFL) fluorescent lamps. The ratio of maximum brightness to minimum (contrast) is 1500 : 1. It is possible to view images in high quality HD at a resolution of 1366x768 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, NTSC. Graphic processing and digital signal generation occurs in standards 480 i, 480p, 576i, 576p, 720p, 1080i Supported media file formats: MP3, MPEG4, JPEG.
The power of the sound system 10 W (2x5 W) provides 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 x3, S-Video, component, 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.
Overall dimensions: With stand 498x371x183 mm, Without stand 439x296x73 mm.
Attention! The BBK LT3219SU 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!