Wednesday, 25 March 2020

REPAIR / SERVICING TV BBK LEM4079F

Technical description and composition of the BBK LEM4079F TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: LEM4079F
Panel: SEL390V7-S00E (WXGA)
LED driver (backlight): 168P-P39DWM-W1
PWM LED driver: OZ9967
Power Supply (PSU): 168P-P39EQL-HCW1 // 168P-P39EQL-HCW0
MainBoard: E182VG-Z0-A0
IC MainBoard: MST6M18VGC-LF-Z, SPI FLASH: 25Q32BVSIG
Tuner: R620D
Control: RC-LEM101
Technical Specifications LEM4079F
BBK LEM4079F
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK LEM4079F TV does not turn on at all. The control lights do not light or flash. On the remote control and the buttons on the control panel does not respond.
With such manifestations, in most cases, the 168P-P39EQL-HCW1 power module is faulty. It is necessary to measure its 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, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
In most cases, the malfunction is caused by the lack of a backlight display. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
To check the LED lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the E182VG-Z0-A0 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements MST6M18VGC-LF-Z, SPI FLASH: 25Q32BVSIG 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.
If there is no reception of television channels, but the TV is working properly from external devices, first of all it is necessary to check the voltage of the R620D tuner and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention TV owners! Attempts at self-repair of BBK LEM4079F are not recommended by the manufacturer and can lead to serious negative consequences!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    LEM3279, LEM3289, LEM3279F, LEM3289F, LEM4079F, LEM4289F, LEM4289F
 Service Manual with Schematic Diagram 58 pages of 2012 on the LEM3279, LEM3289, LEM3279F, LEM3289F, LEM4079F, LEM4289F, LEM4289F models.


The appearance of the MainBoard E182VG-Z0-A0 is shown in the figure below:
E182VG-Z0-A0
E182VG-Z0-A0 can be used in TVs:
BBK LEM3279F (Panel T320HVN01.2 / SEL320V8-S0JB), BBK LEM4079F (Panel SEL390V7-S00E (WXGA)), BBK LEM4279F (Panel SEL420V6-S00E Rev.R1 PCB:C3 LED:S442), BBK LEM4289F (Panel SEL420V6-S00E).
The appearance of the power supply
Main features of the BBK LEM4079F device:
Installed matrix (LED-panel) SEL390V7-S00E (WXGA).
The LED driver 168P-P39DWM-W1 is used to power the backlight LEDs, it is controlled by the OZ9967 PWM controller.
The necessary supply voltages are generated for all nodes of the BBK LEM4079F TV by the power supply module 168P-P39EQL-HCW1, or its analogs.
MainBoard - the main board (motherboard) is an E182VG-Z0-A0 module, using MST6M18VGC-LF-Z microcircuits, SPI FLASH: 25Q32BVSIG and others.
The R620D tuner provides TV reception and channel tuning.

 LED TV BBK LEM4079F with LCD display SEL390V7-S00E, diagonal size 40 "(102 cm) in 16: 9 format. The required brightness of the screen 350 cd / m² is provided by LED backlight LED. The ratio of maximum brightness to minimum (contrast) is 5000 : 1. This model uses Edge LED backlighting, and the design and technical features of the TV include watching broadcasts and movies in high quality HD with a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD). Input high-frequency or video signal It can be processed in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, MKV, JPEG. Stereo audio is implemented in two built-in speakers using NICAM STEREO audio processing system.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, SCART, VGA, HDMI x3, 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, 1360x768.
The power consumed by the TV in the operating mode from the network is 70 watts.
Overall dimensions: With stand 780x546x205 mm, Without stand 780x491x46 mm.
TV Weight: 13 kg.
Attention! The SEL390V7-S00E (WXGA) panel of the BBK LEM4079F LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.