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, 21 April 2020

REPAIR / SERVICING TV DEXP H32B7200C

Technical description and composition of the DEXP H32B7200C TV, panel type and applicable modules. The composition of the modules.
DEXP LED
Model: H32B7200C
Chassis / Version: JUC7.820.00117550
Panel: C320X14-E12-H (G3)
LED backlight: SVJ320AK0 Rev07 6LED 150106 (GD32D2000)
LED driver (backlight): integrated into PSU
PWM LED driver: MP4012
MOSFET LED driver: MDD14N25
Power Supply (PSU): integrated into MainBoard
PWM Power: NCP1251A
MOSFET Power: 7N65
MainBoard: JUC7.820.00117550
IC MainBoard: CPU: 9206B, SPI Flash: GD25Q64, MP1471AGJ
Tuner: CH DMI21-C816RH
Control: IR: JUC7.820.00124415
Technical Specifications H32B7200C
DEXP H32B7200C
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The DEXP H32B7200C TV does not turn on, does not respond to the remote control and the control panel buttons, the indicators do not light or flash.
With such manifestations, a malfunction is most likely to be detected in the power supply combined with this model with elements of the MainBoard main board: JUC7.820.00117550. It is necessary to measure its secondary output voltages, and in case of their absence, check the operability of the power switch 7N65 and rectifier diodes of the AC / DC converter for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during short circuit in the power 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) NCP1251A. It is checked only by replacement with a known good one.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
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 indicator on the front panel blinks, the TV does not turn on in the operating mode, it does not respond to the remote control.
Repair or diagnostics of the JUC7.820.00117550 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). Often, the MB (SSB) card must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: 9206B, SPI Flash: GD25Q64, MP1471AGJ, and replace failed chips with new ones. Some malfunctions may be due to the use of BGA soldering technologies in modern Main Board technologies. Typically, such defects are detected by local heating of the chip.
A malfunction of the tuner CH DMI21-C816RH is established after checking the software and all supply voltages at its terminals. The data exchange of the tuner with the processor via the I2C bus can be controlled by an oscilloscope.
For owners of the H32B7200C TV, we recommend that you contact qualified personnel with the necessary work experience for repairs! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!



Entrance to the Service Menu: SOURCE - 3138

 The appearance of the MainBoard JUC7.820.00117550 is shown in the figure below:
JUC7.820.00117550
JUC7.820.00117550 can be used in TVs:
BBK 32LEM-1018/T2C (Panel C320X14-E12-H), DEXP H32B7200C (Panel C320X14-E12-H(G3)), DEXP H32B7400C (Panel C320X14-E3-H (G7)), ERISSON 32LEC2500 (Panel M320X13-E2-B), TELEFUNKEN LED32S22T2 (Panel M320X13-E1-A).
Main features of the DEXP H32B7200C device:
Installed matrix (LED-panel) C320X14-E12-H (G3).
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the MP4012 PWM controller. As power elements of the LED driver, keys of the MDD14N25 type are used.
The power module is combined with the MainBoard and is designed according to the flyback AC / DC voltage converter using NCP1251A microcircuits and 7N65 type power switches.
MainBoard - the main board (motherboard) is a JUC7.820.00117550 module, using CPU chips: 9206B, SPI Flash: GD25Q64, MP1471AGJ and others.
The CH DMI21-C816RH tuner provides TV reception and channel tuning.
DEXP H32B7200C TV with C320X14-E12-H (G3) LCD, 32 "(81 cm) diagonal size of 16: 9 format. Contrast - the ratio of maximum brightness to minimum is 3000: 1. The LCD panel uses direct pixel illumination with rear LEDs - Direct LED. You can watch broadcasts and movies and 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 is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation LA takes place in the standards 480i, 480p, 576i, 576p, 720p Supported media file formats: MP3, WMA, MPEG4, MKV, JPEG.
The power of the sound system 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, component, VGA, HDMI x3, 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, DVB-C, DVB-T2 standards.
The power consumed by the TV working in the network mode is 45 watts.
Overall dimensions: with stand 740x480x180 mm, without stand 740x420x90 mm.
TV mass: with stand: 5.05 kg, without stand: 4.5 kg.
Attention! The C320X14-E12-H (G3) panel of a DEXP H32B7200C 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 05:27
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