Saturday 18 April 2020

REPAIR / SERVICING TV DEXP F32D7000B

Technical description and composition of the DEXP F32D7000B TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: F32D7000B
Chassis / Version: TP.MS3463S.PB751
Panel: BOEI280WX1
LED backlight: GC32D07-ZC21FG-15 303GC320038
T-CON: HV320FHB-N00
LED driver (backlight): integrated into PSU
MOSFET LED driver: D4454
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MainBoard: TP.MS3463S.PB751
IC MainBoard: SPI Flash: GD25Q64CSIG
Tuner: XF-3SDT-H
Control: IR: 22025B8100P / T
Technical Specifications F32D7000B
DEXP F32D7000B
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F32D7000B TV does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
In this case, first of all, you should check the operability of the main power source - AC / DC network voltage converter, all of whose elements are located on the MainBoard TP.MS3463S.PB751 board. It is necessary to measure its output supply voltage, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in semiconductor PN junctions.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the 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. 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, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
The most likely in these cases is a malfunction of the LED backlight. 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 break in the LED lines without disassembling the panels using 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 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 TP.MS3463S.PB751 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). Board repair and replacement of SPI Flash chips: GD25Q64CSIG are made with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
If you suspect a malfunction of the XF-3SDT-H 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 TV owners! Attempts to self-repair DEXP F32D7000B are not recommended by the manufacturer and can lead to serious negative consequences!

FIRMWARE FOR SPI FLASH  ----------->   DEXP F32D7000B, Main: TP.MS3463S.PB751, Panel: BOEI320WU1

 The appearance of MainBoard TP.MS3463S.PB751 is shown in the figure below:
TP.MS3463S.PB751
Main features of the DEXP F32D7000B device:
Installed matrix (LED-panel) BOEI280WX1.
The matrix control uses the Timing Controller (T-CON) HV320FHB-N00.
To power the backlight LEDs, a converter is used, combined with a power supply. As the power elements of the LED driver, keys of the D4454 type 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.
MainBoard - the main board (motherboard) is a TP.MS3463S.PB751 module, using SPI Flash chips: GD25Q64CSIG and others.
The XF-3SDT-H tuner allows you to receive television programs and tune to channels.
Technical description
DEXP F32D7000B TV with BOEI320WU1 LCD, 32 "(81 cm) diagonal size in 16: 9 format. The required screen brightness of 250 cd / m² is provided by LED backlighting. Contrast - the ratio of maximum brightness to minimum is 800: 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 graphic resolution according to the standard 1080p (Full HD). Supported multi file formats Media: MP3, MPEG4, JPEG.
The power of the sound system 12 W (2x6 W) provides 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.
Overall dimensions: with stand 728x474x180 mm, without stand 728x436x81 mm.
TV Weight: with stand: 3.8 kg, without stand: 3.6 kg.
Attention! The BOEI320WU1 panel of a DEXP F32D7000B 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.