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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Sunday 19 April 2020

REPAIR / SERVICING TV DEXP F48B7000V

Technical description and composition of the DEXP F48B7000V TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: F48B7000V
Chassis / Version: TP.S512.PC821
Panel: LCS480HN07
LED backlight: GZM50 94V-0 1.30.1.94601701R 480N915X12-B0018
LED driver (backlight): integrated into MainBoard
PWM LED driver: LD7750
MOSFET LED driver: 80R900P
Power Supply (PSU): integrated into MainBoard
PWM Power: LD5530 (Stb), NCP1607B (PFC), LD7750 (LED-DRV)
MOSFET Power: 70R900P (Stb), MDF13N50B (PFC)
MainBoard: TP.S512.PC821
IC MainBoard: S2T512, W25Q64BV, TPA3110D2
Tuner: R840 - XF-3SDT-H & T3 / 1 R 1/613
Technical Specifications F48B7000V
DEXP F48B7000V
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F48B7000V 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 main power source, the AC / DC voltage converter, which includes the PFC node and the LED backlight driver, may turn out to be faulty. All power supply nodes are located on the MainBoard TP.S512.PC821 main board. It is necessary to measure all the output voltages of the source, and in case of their absence, the power switches and rectifier diodes should be checked in the converters for a short circuit.
In case of breakdowns of semiconductors in secondary circuits, the converter can usually operate abnormally in short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback (OOS) stabilization circuits. PWM controllers (PWM) NCP1607, LD5530, LD7750, if they do not have visible damage to the case and open short circuit between the terminals, are usually 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.
In most of these cases, a malfunction is detected in the nodes and backlight elements of the LED panel. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
It should be remembered that it is not possible to determine the open circuit in the LED lines without disassembling the panels with a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then it is necessary to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow you to open the LED in the forward direction or dual LEd are used, then the PN junction of the emergency zener diode can indirectly serve as a health indicator. In case of LED-a failure, the zener diode PN junction will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the TP.S512.PC821 motherboard should be started by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - S2T512, W25Q64BV, TPA3110D2. Defective components should be replaced.
If there is no reception of television channels, but the TV works properly from external devices, first of all you need to check the voltage of the tuner R840 - XF-3SDT-H & T3 / 1 R 1/613 and update the software. The pulses from the I2C bus must be controlled with an oscilloscope.
Attention! For users and owners of F48B7000V TVs who do not have the appropriate qualifications, knowledge and experience, we categorically do not recommend attempting self-repair in order to avoid negative consequences that could lead to complete non-repairability of the device.

 SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    MainBoard TP.S512.PC821

FIRMWARE FOR SPI FLASH  ----------->   DEXP F48B7000V, Main: TP.S512.PC821, Panel: LCS480HN07

 The appearance of MainBoard TP.S512.PC821 is shown in the figure below:
TP.S512.PC821
TP.S512.PC821 can be used in TVs:
AKAI LEA-49K40M (Panel LSC490HN04-W), DEXP F48B7000V (Panel LCS480HN07), SHIVAKI STV-48LED15 (Panel LSC480HN05-B01), SHIVAKI STV-49LED17 (Panel LSC490HN03-W), SHIVAKI STV-50LED13 (Panel V500HJ1-PE8), THOMSON T48D16SF-01B (Panel LVF480SSDX E8 V1).
Main features of the DEXP F48B7000V device:
Installed matrix (LED panel) LCS480HN07.
To power the backlight LEDs, a converter is used, combined with the TP.S512.PC821 main board, controlled by the LD7750 PWM controller. As the power elements of the LED driver, keys of the 80R900P type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using the LD5530 (Stb), NCP1607B (PFC), LD7750 (LED-DRV) microcircuits and power switches of the type 70R900P (Stb), MDF13N50B (PFC).
MainBoard - the main board (motherboard) is a module TP.S512.PC821, with the use of chips S2T512, W25Q64BV, TPA3110D2 and others.
The tuner R840 - XF-3SDT-H & T3 / 1 R 1/613 provides the reception of television programs and tuning to channels.
TV DEXP F48B7000V with LCD display LCS480HN07, diagonal size 48 "(122 cm) 16: 9 format. The required brightness of the screen 350 cd / m² is provided by LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 1000: 1. In LCD -panels use direct LED backlighting with direct LEDs - Direct LED.The 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 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, 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), 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, 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 1100x717x240 mm, without stand 1100x662x83 mm.
The mass of the TV: without stand: 16 kg.
Attention! The LCS480HN07 panel of a DEXP F48B7000V 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 06:41
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