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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Saturday 18 April 2020

REPAIR / SERVICING TV DEXP 50A7000

Technical description and composition of the DEXP 50A7000 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 50A7000
Chassis / Version: JUC7.820.00084054
Panel: C500F13-E3-A
LED backlight: CH50L31A-V01 - DSBJ-SS
T-CON: T500HVD02.0 CTRL BD 50T10-C02
LED driver (backlight): integrated into PSU
Power Supply (PSU): R-HSM45D-6M4
MainBoard: JUC7.820.00084054 HLS49J 32C2000
IC MainBoard: 25Q64, H5TQ1G630FR, RT9108NB, MSB101A
Tuner: DT21WN-2A-E
Specifications 50A7000
DEXP 50A7000
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 50A7000 TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
Failure in such cases should begin to be sought in the power supply circuits of R-HSM45D-6M4. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of the power switches of the converters and rectifier diodes for the presence of a possible short circuit.
In the event of breakdowns in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the mains fuse or current sensor at the source of the key most often breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM microcircuits are usually checked by replacement with new ones, or obviously working.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
In such cases, the most likely malfunction of the LED backlight elements. 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 strips, to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the JUC7.820.00084054 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 cases of attempts to repair the MB board (SSB), it is necessary to check the health of its elements - 25Q64, H5TQ1G630FR, RT9108NB, MSB101A which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its conclusions with the board (it is diagnosed by heating).
If you suspect a malfunction of the DT21WN-2A-E tuner, first of all, you need to verify the correctness of the software, as well as the presence of the necessary voltage levels and pulses of data exchange with the processor via the I2C bus at the corresponding terminals of the tuner.
Attention to users! Self-repair of a DEXP 50A7000 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!
FIRMWARE FOR SPI FLASH  ----------->   DEXP 50A7000, Main: JUC7.820.00084054 HLS49J 32C2000, Panel: C500F13-E3-A


 The appearance of the MainBoard LS1B is shown in the figure below:
LS1B
JUC7.820.00084054 can be used in TVs:
BBK 40LEM-3080/FT2C (Panel ECG390AH-LD2 (SN)), BBK 32LEM-3081/T2C (Panel M320X13-E2-H), BBK 32LEM-1003/T2C (Panel M320X13-E4-L HD), DEXP 28A3000 (Panel R-HS055D-1MF), DEXP 50A7000 (Panel C500F13-E3-A), DNS C28DC2000 (Panel M280X13-E1-H), DNS C39DC2000 (Panel M390F13-E1-A), ERISSON 42LEC2000 (Panel M420F13-E1-L (G1)), ERISSON 55LEC2000 (Panel M550F13-E1-A 1080p Full HD), ERISSON 28LEC2000 (Panel M280X13-E1-H), RUBIN RB-32SD8T2C (Panel M320X13-E3-H), TELEFUNKEN TF-LED32S12T2 (Panel M320X12-E9-A(1)).
The appearance of the power supply
Main features of the DEXP 50A7000 device:
Installed matrix (LED-panel) C500F13-E3-A.
The matrix control uses the Timing Controller (T-CON) T500HVD02.0.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the DEXP 50A7000 TV is carried out by the power module R-HSM45D-6M4, or its analogues.
MainBoard - the main board (motherboard) is a JUC7.820.00084054 module, using 25Q64, H5TQ1G630FR, RT9108NB, MSB101A and other chips.
Tuner DT21WN-2A-E provides the reception of television programs and tuning to channels.
DEXP 50A7000 TV with C500F13-E3-A LCD, 50 "(127 cm) diagonal size of 16: 9 format. The required brightness of the screen is 330 cd / m² LED backlighting. Contrast - the ratio of maximum brightness to minimum is 3000: 1. This model uses a panel with the end position of the backlight LEDs - Edge LED.The TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in graphic resolution according to the standard 1080p (Full HD). Input high-frequency or video signal l decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, DivX, MKV, JPEG .
The power of the acoustic system of sound 20 W (2x10 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), component, VGA, HDMI x3, USB. 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, 1280x1024, 1360x768, 1920x1080. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 1120x700x262 mm, without stand 1120x645x65 mm.
TV Weight: with stand: 15 kg, without stand: 14.2 kg.
Attention! The C500F13-E3-A panel of a DEXP 50A7000 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 06:03
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