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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Monday 23 March 2020

REPAIR / SERVICING TV BBK 39LEM-1045

Technical description and composition of the BBK 39LEM-1045 TV, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: 39LEM-1045 / T2C
Chassis / Version: CV512H-U42
Panel: T390XVN02.0 AUO
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267 PWM 8pin
MOSFET LED driver: ME15N10-G
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: CV512H-U42
IC MainBoard: SPI Flash: W25Q64
Tuner: CDT-9NT372-RD60
Specifications 39LEM-1045 / T2C
BBK 39LEM-1045
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK 39LEM-1045 TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
In such cases, the AC / DC voltage converter, which is combined with the main board CV512H-U42, is often faulty. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches and rectifier diodes in the converters for a short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM SOT23-6 PWM controllers, in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- 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.
The most likely in these cases is a malfunction of the LED backlight. 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.
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 a health indicator. 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 CV512H-U42 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). In some cases, to repair the MB board (SSB), it may be necessary to replace the chips - SPI Flash: W25Q64 with new or obviously good ones. In cases where BGA technologies are used, defects are usually localized by the heating method.
Before changing the tuner CDT-9NT372-RD60, if it is not possible to tune to television channels, make sure that there are supply voltages that need to be measured at the corresponding terminals of the tuner and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
Owners and users of the BBK 39LEM-1045 TV should remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences that can lead to complete non-repairability of the device!



The appearance of the MainBoard CV512H-U42 is shown in the figure below:
CV512H-U42
CV512H-U42 can be used in TVs:
DEXP H39D7000Q (Panel LC390TA2A), SUPRA STV-LC32LT0010W (Panel KM0320LDRH0037).
Main features of the BBK 39LEM-1045 device:
Installed matrix (LED-panel) T390XVN02.0 AUO.
To power the backlight LEDs, a converter is used, combined with the main board CV512H-U42, controlled by a BIT3267 PWM 8pin PWM controller. As the power elements of the LED driver, keys of the type ME15N10-G are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits and TO-252 type power switches.
MainBoard - the main board (motherboard) is a CV512H-U42 module, using SPI Flash chips: W25Q64 and others.
The tuner CDT-9NT372-RD60 provides the reception of television programs and tuning to channels.
Brand: BBK, Model: 39LEM-1045 / T2C.
Briefly from the TV: LCD, LED backlight, 38.5 ", 1366x768, 720p HD, DVR, sound: 16W, HDMI connectors: 3.
Manufacturer: TELEBALT Kaliningrad, Kamskaya, 62. The assembly can be in the city of Guards, st. Station, 6 (PKV).
Developer: BBK Electronics LTD. China
The composition uses MainBoard CV512H-U42 and LCD-panel T390XVN02.0 AUO. The power supply is combined with the MainBoard.
BBK 39LEM-1045 / T2C LED TV with T390XVN02.0 LCD, 38.5 "(98 cm) diagonal, 16: 9 aspect ratio. The required screen brightness of 250 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum ( contrast ratio) is 5000: 1. The LED display backlighting technology is implemented in the model’s display technology. High quality HD images can be viewed at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). Supported media file formats: MP3, MPEG4, HEVC (H .265), MKV, JPEG.
The power of the sound speaker system 16 W (2x8 W) is provided by 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, component, VGA, HDMI x3, USB. An output for connecting headphones is provided. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
The power consumed by the TV in the operating mode from the network is 70 watts.
Overall dimensions: with stand 883x558x192 mm, without stand 883x513x76 mm.
The mass of the TV: 5.2 kg.
Attention! The T390XVN02.0 AUO panel of the BBK 39LEM-1045 / 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.

Posted By: FRANK at 05:57
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