Saturday 21 March 2020

REPAIR / SERVICING TV BBK 19LEM-1015

Technical description and composition of the BBK 19LEM-1015 TV, panel type and applicable modules. The composition of the modules.
BBK LED
Model: 19LEM-1015 / T2C
Chassis / Version: JUC7.820.00128709
Panel: C185X14-E5-P
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
Power Supply (PSU): Adapter 12V
MainBoard: JUC7.820.00128709
IC MainBoard: SPI Flash: 25Q64, Audio: YD1517P
Tuner: CH DMI21-8I6RH / 5508FW
Technical Specifications 19LEM-1015 / T2C
BBK 19LEM-1015
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK 19LEM-1015 does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
With such manifestations, a malfunction is most likely to be detected in the Adapter power module.
The external adapter 12V power supply is not always subject to repair, especially since the owner can purchase it independently. But, in some cases, it makes sense to open it and eliminate the simple typical defects inherent in converters in pulsed sources. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches and rectifier diodes for a possible partial or complete breakdown.
In case of diode breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key 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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM), in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, there is sound, it responds to the remote. Or the image may appear for a second when turned on and immediately disappears.
Often in such cases, there is no LED backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It is impossible to check the line of series-connected LEDs without a special current source, and for this purpose it is not safe to use any voltage sources above 12V for them. Then it remains only to open the panel and check each LED separately. Usually, Chinese 9V-powered multimeters light up a single 3-volt LED, if you connect the probes in the forward direction, the red probe to the anode, and the black to the cathode. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the JUC7.820.00128709 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). Board repair and chip replacement SPI Flash: 25Q64, Audio: YD1517P are made with the necessary equipment, and the corresponding hardware base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
Before changing the CH DMI21-8I6RH / 5508FW tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that need to be measured on 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
TV users and owners must remember that attempts to self-repair a BBK 19LEM-1015 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!


FIRMWARE FOR SPI FLASH  ----------->   BBK 19LEM-1015/T2C, Main: JUC7.820.00128709, Panel: C185X14-E5-P

 The appearance of the MainBoard JUC7.820.00128709 is shown in the figure below:
JUC7.820.00128709
JUC7.820.00128709 can be used in TVs:
BBK 24LEM-1015/T2C (Panel C240X14-E3-C (G6)), BBK 19LEM-1015/T2C (Panel C185X14-E5-P), SUPRA STV-LC22T440FL (Panel C215F14-E5-P).
Main features of the BBK 19LEM-1015 device:
Installed matrix (LED-panel) C185X14-E5-P.
To power the backlight LEDs, a converter is used, combined with the main board JUC7.820.00128709, controlled by the OB3350CP PWM controller.
To power all the internal components of the BBK 19LEM-1015 TV, an external adapter 12V type is used.
MainBoard - the main board (motherboard) is a JUC7.820.00128709 module, using SPI Flash chips: 25Q64, Audio: YD1517P and others.
The CH DMI21-8I6RH / 5508FW tuner provides TV reception and channel tuning.


 Brand: BBK, Model: 19LEM-1015 / T2C.
Briefly from the TV: LCD, 720p HD, diagonal 19 "(48 cm), there is HDMI, there is USB, there is support for DVB-T2, the type of backlight: Edge LED.
The composition uses MainBoard JUC7.820.00128709 and an LCD panel (matrix) C185X14-E5-P.
Power supply unit external Adapter 12V.
BBK 19LEM-1015 / T2C LED TV with C185X14-E5-P LCD, 19 "(48 cm) diagonal of 16: 9 format. The required screen brightness of 180 cd / m² is provided by LED backlighting. The ratio of maximum brightness to the minimum (contrast ratio) is 600: 1. This model uses side illumination from Edge LEDs. You can view images in high quality HD with 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 PAL, SECAM, NTSC systems. Kaya processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats:. MP3, MPEG4, MKV, JPEG.
The power of the sound system 6 W (2x3 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, 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, 1360x768. The digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C MPEG4, DVB-T2 standards.
Overall dimensions: With stand 442x299x165 mm, Without stand 442x263x53 mm.
TV Weight: 3.05 kg.
Attention! The C185X14-E5-P panel of a BBK 19LEM-1015 / T2C 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.