Saturday 18 April 2020

REPAIR / SERVICING TV DEXP F22D7200E

Technical description and composition of the DEXP F22D7200E TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: F22D7200E / W
Chassis / Version: TP.MS3663S.PA671
Panel: ST2151B01-1
LED backlight: Edge LED
T-CON: ST2151B01-1-XC-9
LED driver (backlight): integrated into MainBoard
PWM LED driver: 8pin
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: TO-252
MainBoard: TP.MS3663S.PA671
IC MainBoard: CPU: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P
Tuner: CDT-9NT372-RF01
Technical Specifications F22D7200E / W
DEXP F22D7200E
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F22D7200E 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.
The malfunction in such cases should be sought in the elements of the power source - the line voltage converter (AC / DC), which is located on the MainBoard TP.MS3663S.PA671 main board. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (TO-252) and the rectifier diodes of the converters for the probability of a short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key more often breaks.
Mos-Fet power switches, used in switching power supplies, sometimes fail due to a malfunction of any other elements that can put it out of operation in key mode, or create an excess of the maximum permissible parameters of the switch. These can be elements supplying the PWM controller, frequency-setting or damping circuits, or negative feedback elements in the stabilization circuit. PWM SOT23-6 PWM controllers, in the absence of visible damage or obvious short-circuit between the terminals, are checked by replacing with new ones, or obviously working.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
As a rule, in this case, the LED backlight turns out to be faulty. The reason can sometimes be in the power of the LEDs, but more often in their malfunction (breakdown or break), sometimes in the violation of the contact connections of the LED strips.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- 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.MS3663S.PA671 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). Sophisticated MB board repair (SSB) is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the CPU elements: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P. BGA chip malfunctions are usually easy to detect by warming up.
Before replacing the tuner CDT-9NT372-RF01, if there is no tuning for the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Attention TV owners! Attempts to self-repair DEXP F22D7200E are not recommended by the manufacturer and can lead to serious negative consequences!


FIRMWARE FOR SPI FLASH  ----------->   DEXP F22D7200E/W, Main: TP.MS3663S.PA671, Panel: ST2151B01-1


 The appearance of MainBoard TP.MS3663S.PA671 is shown in the figure below:
TP.MS3663S.PA671
Main features of the DEXP F22D7200E device:
Installed matrix (LED panel) ST2151B01-1.
The matrix control uses the Timing Controller (T-CON) ST2151B01-1-XC-9.
To power the backlight LEDs, a converter is used, combined with the TP.MS3663S.PA671 main board, controlled by an 8pin PWM controller.
The power module is combined with the MainBoard and is designed according to a flyback AC / DC voltage converter using PWM SOT23-6 microcircuits and TO-252 type power switches.
MainBoard - the main board (motherboard) is a TP.MS3663S.PA671 module, using CPU chips: MSD3663LSA-Z1, SPI FLASH MX25L6436F, AUDIO: YD1517P and others.
The tuner CDT-9NT372-RF01 provides the reception of television programs and tuning to channels.
TV DEXP F22D7200E / W with LCD display ST2151B01-1, diagonal size 22 "(56 cm) 16: 9 format. The required brightness of the screen 180 cd / m² is provided by LED backlight LED. Contrast - the ratio of maximum brightness to minimum is 3000: 1. The LCD panel uses direct pixel illumination with rear LEDs - Direct LED. Media: MP3, WMA, MPEG4, MKV, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, VGA, HDMI, USB. An output for connecting headphones is provided. The digital tuner is capable of receiving television channels in the standards DVB-T MPEG4, DVB-C, DVB-T2, DVB-S2.
The power consumed by the TV working in the network mode is 36 watts.
Overall dimensions: with stand 510x340x165 mm, without stand 510x307x75 mm.
TV Weight: with stand: 2.2 kg, without stand: 2 kg.
Attention! The ST2151B01-1 panel of a DEXP F22D7200E / W 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.