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 LED1972DTG

Technical description and composition of the BBK LED1972DTG TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: LED1972DTG
Chassis / Version: L1M04
Panel: V185B1-LE1 Rev: C1
LED backlight: V185B1-LE1-TREF6 - 18 LED
LED driver (backlight): LDA15-42V160H
Power Supply (PSU): L-CEM1
PWM Power: LD7535 (PWM 6 pin)
MainBoard: L1M04 (00) DVD 237-N-BBK-8 + 8
IC MainBoard: CPU: MSD309PX-LF-Z1, SPI FLASH: Winbond 25Q32, AUDIO: YD1517
Tuner: NoName
Control: RC-LED100
Technical Specifications LED1972DTG
BBK LED1972DTG
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The BBK LED1972DTG TV does not turn on and does not show any signs of turning on at all. There are no reactions to the control buttons or the remote control.
With such manifestations, a malfunction is most likely to be detected in the power module. It is necessary to measure the output voltages in the secondary circuits, 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.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power, 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 is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. 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 TV does not enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the L1M04 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).

Attention to users! Self-repair of the BBK LED1972DTG TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

 FIRMWARE FOR SPI FLASH  ----------->   BBK H-LED1972DTG L1M04, Main: L1M04 (00) DVD 237-N-BBK-8+8, Panel: V185B1-LE1 Rev:C1


 The appearance of the MainBoard L1M04 is shown in the figure below:
L1M04
The appearance of the power supply
Main features of the BBK LED1972DTG device:
Installed matrix (LED-panel) V185B1-LE1 Rev: C1.
The LED driver LDA15-42V160H is used to power the backlight LEDs.
The necessary supply voltages for all nodes of the BBK LED1972DTG TV are generated by the L-CEM1 power module or its analogs using LD7535 microcircuits (PWM 6 pin).
MainBoard - the main board (motherboard) is an L1M04 module using CPU chips: MSD309PX-LF-Z1, SPI FLASH: Winbond 25Q32, AUDIO: YD1517 and others.
The NoName tuner provides television reception and channel tuning.
Additional technical information about the panel:
Brand: CMO
Model: V185B1-LE1
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 (8-bit), CIE1931 70%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 13S8P WLED Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V

 Brand: BBK, Model: LED1972DTG.
Briefly from the TV: LCD, 720p HD, diagonal 19 "(48 cm), HDMI: 2, USB, backlight type: Edge LED.
The composition includes MainBoard L1M04 (00) DVD 237-N-BBK-8 + 8 and LCD panel (matrix) V185B1-LE1 Rev: C1.
Power Supply Unit (PSU) L-CEM1 Power Supply.
BBK LED1972DTG LED TV with V185B1-LE1 LCD, 19 "(48 cm) diagonal, 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 for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC . Graphic I process and generate digital signals in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, MKV, VideoCD, SVCD, Picture CD, JPEG.
The power of the acoustic system of sound 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, audio x2, 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, 1920x1080. 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: 476x354x115 mm.
The mass of the TV: 4.2 kg.
Attention! The V185B1-LE1 Rev: C1 panel of the BBK LED1972DTG 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 05:44
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