Thursday 19 March 2020

REPAIR / SERVICING TV BBK LD1913SU

Technical description and composition of the BBK LD1913SU TV, type of panel and applicable modules. The composition of the modules.
BBK
Model: LD1913SU
Chassis / Version: L2M18 (03)
Panel: HT185WX1-100
Inverter (backlight): LK-IN150211A
PWM Inverter: LT927 (OD3316NQP)
MOSFET Inverter: ME4946 (G927)
Trans Inverter: LKT-024CFD 0934
Power Supply (PSU): HGP-KS03 / REV 5-2
PWM Power: LD7575PS (PWM flyback)
MOSFET Power: B59505
MainBoard: L2M18 (03)
IC MainBoard: MST9U19B-LF (A6MFG73H), MP2307DN
Tuner: AFT7 / W102G
Technical Specifications LD1913SU
BBK LD1913SU
General recommendations for repairing TV LCD
Possible malfunctions
- The BBK LD1913SU TV does not turn on and does not show any sign of turning on at all. There are no reactions to the control buttons or the remote control.
Most likely in this case, the main switching power supply (IIP) HGP-KS03 is faulty. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is first necessary to check the power switches (B59505) and rectifier diodes for a possible partial or complete breakdown.
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 key may be PWM (PWM) LD7575PS (PWM flyback). It is checked only by replacement with a known good one.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately 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. After checking all the electrolytic capacitors of the filters that are involved in the power supply of the inverter, it is necessary to ring in its converter the power switches for breakdown and the 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, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the L2M18 (03) 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). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - MST9U19B-LF (A6MFG73H), MP2307DN. Defective components should be replaced.
Before changing the AFT7 / W102G tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
We recommend the owners of the LD1913SU TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!


SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    BBK LD1913SU



Service Manual with Schematic Diagram 21 pages 2007  model LD1913SU, LD2213SU



 The appearance of the MainBoard L2M18 (03) is shown in the figure below:
L2M18 (03)
L2M18 (03) can be used in TVs:
BBK LD1913SU (Panel HT185WX1-100), BBK LD2213SU Ver1 (Panel M216H1-L01 RevC1 LTA216AT01), BBK LD2213SU Ver2 (Panel LCD LC220WXE-TBA1), SHIVAKI STV-22L6 (Panel L216B1-L02 Rev.C1).
Main features of the BBK LD1913SU device:
Installed matrix (LCD panel) HT185WX1-100.
To power the backlight, an LK-IN150211A inverter is used, controlled by the LT927 PWM controller (OD3316NQP). A transformer LKT-024CFD 0934 is installed in the inverter converter. Keys of the type ME4946 (G927) are used as power elements of the inverter.
The necessary supply voltages for all nodes of the BBK LD1913SU TV are generated by the HGP-KS03 power module or its analogs using LD7575PS (PWM flyback) microcircuits and B59505 type power switches.
MainBoard - the main board (motherboard) is an L2M18 (03) module, using microchips MST9U19B-LF (A6MFG73H), MP2307DN and others.
The AFT7 / W102G tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: BOE
Model: HT185WX1-100
Type: a-Si TFT-LCD, Panel
Diagonal size: 18.5 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 409.8x230.4 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 250 cd / m²
Contrast Ratio: 1000: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.5 / 3.5 (Tr / Td)
Frequency: 60Hz
Lamp Type: 2 pcs CCFL Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V

 Brand: BBK, Model: LD1913SU.
Shortly from the TV: LCD, 720p HD, diagonal 19 "(48 cm), there is HDMI, there is USB.
The composition uses MainBoard L2M18 (03) and an LCD panel (matrix) HT185WX1-100.
Power Supply Unit (PSU) HGP-KS03 / REV 5-2 Power Supply.


BBK LD1913SU LCD TV with HT185WX1-100 LCD, 19 "(48 cm) diagonal display in 16: 9 format. 250 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Maximum brightness to minimum ratio (contrast) ) is 800: 1. It is possible to view images in high quality HD at a resolution of 1366x768 pixels in the standard for 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 stand ports 480i, 480p, 576i, 576p, 720p, 1080i Supported media file formats: WMA, MPEG4, VideoCD, SVCD, Picture CD, JPEG. Stereo sound is realized by two built-in speakers. NICAM STEREO audio processing system is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), component, SCART, RGB, VGA, HDMI, 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 60 watts.
Overall dimensions: 457x356x170 mm.
TV Weight: 4.8 kg.

Attention! The BB18 LD1913SU LCD TV panel HT185WX1-100 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!