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 42A7000

Technical description and composition of the DEXP 42A7000 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 42A7000
Chassis / Version: TP.S512.PB83
Panel: CX420DLEDM
LED backlight: RF-AD420E32-1201S-03 A1
T-CON: 6870C-0469A V14 42 DRD TM120 Control_Ver 1.4B
LED driver (backlight): integrated into MainBoard
PWM LED driver: SN510P
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: TP.S512.PB83
IC MainBoard: CPU: S2T512, SPI Flash: 25Q64, Sound: TPA3110LD2, RT9108NB
Tuner: XF-3SDT-H (R840)
Specifications 42A7000
DEXP 42A7000
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 42A7000 TV does not turn on at all. There is no reaction to the remote control and control buttons from the front panel. Indicator lights do not light or flash.
First of all, in such cases, you should verify the operability of the common switching power supply (IIP) - AC / DC voltage converter of the mains voltage. All source elements in this TV model are located on the MainBoard TP.S512.PB83 main board. 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 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.
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. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) PWM SOT23-6, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- 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.
As a rule, in such cases there is no display 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.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can check each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- 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 TP.S512.PB83 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits 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: S2T512, SPI Flash: 25Q64, Sound: TPA3110LD2, RT9108NB 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.
If there is no reception of television channels, but the TV is working properly from external devices, first of all you need to check the voltage of the tuner XF-3SDT-H (R840) and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
It should be remembered! Attempts to independently repair the DEXP 42A7000 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!

 FIRMWARE FOR SPI FLASH  ----------->   DEXP 42A7000, Main: TP.S512.PB83, Panel: CX420DLEDM


 The appearance of MainBoard TP.S512.PB83 is shown in the figure below:
TP.S512.PB83
TP.S512.PB83 can be used in TVs:
AKAI LEA-39V51P (Panel LC390TA2A 902-P05-390H ), DEXP 40A7000 (Panel C400F13-E2-C), DEXP F39B7100E (Panel T390HVN04.0 CX390DLEDM), DEXP H32B7000C (Panel T320XVN02.9 C320X14-E2-A), DEXP F42B7000ED (Panel CX420DLEDM), DEXP F32C7000B (Panel BOEI320WU1), DEXP F32C7100B/W F32C7100 (Panel BOEI320WU1), DEXP 32A7000 (Panel BOEI320WU1), DEXP 42A7000 (Panel CX420DLEDM), DEXP F32B7000B (Panel BOEI320WU1), DEXP H39D7000E (Panel CX390DLEDM), DEXP F40B7000C (Panel C400F13-E2-C), DEXP H32B3200CD (Panel HV320WX2-201), HAIER LE28F6000T (Panel A275HD1A01-2 / LVW280CSDO E2 V2), HAIER LE32F6000T (Panel ST3151A05-8 LVW320CSDX E13 V2), MYSTERY MTV-4025LT2 (Panel CX400DLEDM), SHIVAKI STV-32LED13 (Panel SV320SHD PDL320TU2A X41), SHIVAKI STV-42LED16 (Panel V420HJ-P01), SHIVAKI STV-32LED14 (Panel CX315DLEDM AJ32TO3), SHIVAKI STV-40LED13W (Panel V400HJ6PE1-C2), SHIVAKI STV-32LED15 (Panel HV320WHB-N80), SUPRA STV-LC32T440WL (Panel C320X14-E13-H), SUPRA STV-LC32T900WL (Panel LC320TU3A), SUPRA STV-LC40T900FL (Panel 1080p Full HD 1920x1080), THOMSON T32D15DH-01B (Panel LVW320CSDX E13 V30), THOMSON T28D15DH-01B (Panel LVW280CSDE E3 V5), THOMSON T32D16DH-01W T32D16DH (Panel LVW320CSDX E19 V28), THOMSON T43D16SF-01B T43D16SF (Panel LVF430LGDO E2 V18).
Main features of the DEXP 42A7000 device:
Installed matrix (LED-panel) CX420DLEDM.
The matrix control uses the Timing Controller (T-CON) 6870C-0469A.
To power the backlight LEDs, a converter is used, combined with the TP.S512.PB83 main board, controlled by the SN510P PWM controller.
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.
MainBoard - the main board (motherboard) is a TP.S512.PB83 module, using CPU chips: S2T512, SPI Flash: 25Q64, Sound: TPA3110LD2, RT9108NB and others.
Tuner XF-3SDT-H (R840) provides the reception of television programs and tuning to channels.
DEXP 42A7000 TV with CX420DLEDM LCD, 42 "(107 cm) diagonal size in 16: 9 format. The required brightness of the screen is 250 cd / m² LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 1200: 1. In LCD - panels use direct LED backlighting - Direct LED. TV features include viewing programs and movies in high quality HD at a resolution of 1920x1080 pixels in the graphic resolution of the standard 1080p (Full HD). Input high-frequency or video signal The channel is decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, MPEG4, 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), AV, audio x2, 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, 1280x1024, 1360x768, 1920x1080. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Mass of the TV: 11.5 kg.
Attention! The CX420DLEDM panel of a DEXP 42A7000 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 05:42
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