REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

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Tuesday 24 March 2020

REPAIR / SERVICING TV BBK LEM1968DT

Technical description and composition of the BBK LEM1968DT TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: LEM1968DT Ver1
Chassis / Version: 0576 Kaliningrad
Panel: V185B1-LE1 Rev. C1
LED driver (backlight): LDA15-42V160H
PWM LED driver: BIT3251 (8)
MOSFET LED driver: B6010D EP54639 Y1117 (3),
Trans LED driver: 470
PWM Power: PWM SOT23-6
MainBoard: L0M05 (00)
IC MainBoard: CPU: MSD309PX-LF-Z1; Spi Flash: 25Q32 Ram: W9751G6JB-25; YD1517P, MP1484EN (8),
Tuner: R620D
Control: RC1968
BBK LED
Model: LEM1968DT Ver2
Chassis / Version: LM05 (02)
Panel: E185SG01 01
LED driver (backlight): F782003311
PWM LED driver: BIT3251 (8),
MOSFET LED driver: ME15N10-G (3)
Power Supply (PSU): FSE060E0
PWM Power: PWM SOT23-6
MainBoard: LM05 (02) 2012.03.06
IC MainBoard: Cpu: MSD309PX-LF-Z1, Spi Flash: 25Q32BVSIG, Sdram: W9751G6KB-25, Converter: RT7237AN, Audio amp: УD1517P
Control: RC-LEM100
Technical Specifications LEM1968DT
BBK LEM1968DT
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK LEM1968DT TV does not turn on. There are no signs of operability. The indicators on the front panel do not shine and do not blink, and the remote control and control buttons do not respond.
In such cases, the fault should be sought first in the FSE060E0 power supply module. It is necessary to measure the secondary output voltages, 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 a 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 also be PWM PWM SOT23-6. It is checked only by replacement with a known good one.
- 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.
In such cases, the most likely malfunction of the LED backlight elements. The reason can be both in the power of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
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. 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 LM05 (02) 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 (SSB) board, you need to check the health of its elements - Cpu: MSD309PX-LF-Z1, Spi Flash: 25Q32BVSIG, Sdram: W9751G6KB-25, Converter: RT7237AN, Audio amp: УD1517P. Defective components should be replaced.
TV users and owners need to remember that attempts to self-repair a BBK LEM1968DT TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
Service Manual with Schematic Diagram 73 pages of 2011 on the LEM1968DT, LEM2268FDT, LEM2468FDT.
SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    LEM1968DT LEM2268FDT LEM2468FDT (MSD309)



 MainBoard L0M05 uses the MSD309B processor, a BGA version of the DDRAM random access memory (RAM) and 25Q32 type SPI Flash ROM (4Mb).
It is advisable to start the repair of the motherboard by checking the voltage converters and linear stabilizers necessary to provide power to the nodes in the operating and standby modes. The processor core is powered by + 1.5V. Also, the processor voltage requires + 2.5V and + 3.3V.
If the display backlight is OK and there is no image, it is necessary to check the panel power (depending on the type, + 5V or + 12V), which is more convenient to measure directly on the LVDS connector. If, in the presence of all the supply voltages, the TV does not enter the operating mode, does not respond to the Remote Control and control buttons, you should update the SPI Flash firmware.
The appearance of the MainBoard L0M05 is shown in the figure below:
The appearance of the power supply
Main features of the BBK LEM1968DT device:
Installed matrix (LED-panel) E185SG01 01.
The LED driver F782003311 is used to power the backlight LEDs, it is controlled by the BIT3251 PWM controller (8),. As the power elements of the LED driver, keys of the type ME15N10-G (3) are used.
The necessary supply voltages for all nodes of the TV BBK LEM1968DT are generated by the FSE060E0 power module or its analogs using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is an LM05 (02) module, using Cpu microcircuits: MSD309PX-LF-Z1, Spi Flash: 25Q32BVSIG, Sdram: W9751G6KB-25, Converter: RT7237AN, Audio amp: YD1517P and others.

 BBK LEM1968DT LED TV with E185SG01 LCD, 19 "(48 cm) diagonal size in 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 1000: 1 This model uses side illumination from Edge LEDs. You can 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. GraphicDigital signal processing and generation takes place in the standards 480i, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide 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 x2, SCART, 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, 1360x768. The digital tuner is capable of receiving television channels in DVB-T MPEG4 standards.
The power consumed by the TV in the operating mode from the network is 30 watts.
Overall dimensions: 470x341x150 mm.
Mass of the TV: 3.3 kg.
Attention! The E185SG01 01 panel of the BBK LEM1968DT 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.
Posted By: FRANK at 07:55
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