Friday 17 April 2020

REPAIR / SERVICING TV DEXP 22A7100

Technical description and composition of the DEXP 22A7100 TV, type of panel and applicable modules. The composition of the modules.
DEXP LED
Model: 22A7100
Chassis / Version: CV9202L-T
Panel: T215HVN01.0 M215HVN01.0
LED backlight: EDGE LED RF-AD215C14-1006S-02A2
T-CON: M215HVN01.0 CTRL BD 21M07-C02; AUO-12304
LED driver (backlight): integrated into PSU
PWM LED driver: OB3350CP
MOSFET LED driver: AOD450
Power Supply (PSU): MP24S-CX
PWM Power: OB2273 (PWM SOT23-6)
MainBoard: CV9202L-T
IC MainBoard: Cpu: SPV9202BD, DDRAM: W6310GKB-12, Spi Flash: 25Q64, SOUND: YD1517
Tuner: ST03WS-2A-E
Control: IR: CX-2418-IR VER1.0
Specifications 22A7100
DEXP 22A7100
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP 22A7100 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 some of these cases, the main switching power supply, the MP24S-CX module, is faulty. It is necessary to measure its output voltages and, if they are absent, to check the short circuit probability in the converters power switches and rectifier diodes.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse 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-controllers OB2273 (PWM SOT23-6), in the absence of visible damage or frank short-circuit between the terminals, are checked by replacing with new, 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.
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 lines for breaks without disassembling the panel, for example, a current source will help. It is impossible to open series-connected PN junctions with a simple multimeter, a voltage of the order of several tens of volts is required.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the CV9202L-T 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements Cpu: SPV9202BD, DDRAM: W6310GKB-12, Spi Flash: 25Q64, SOUND: YD1517 requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
If you suspect a malfunction of the ST03WS-2A-E 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 to users! Self-repair of the DEXP 22A7100 TV without the appropriate qualifications and the necessary experience can lead to its complete non-repairability!

FIRMWARE FOR SPI FLASH  ----------->   DEXP 22A7100, Main: CV9202L-T, Panel: T215HVN01.0
 
 The appearance of the MainBoard CV9202L-T is shown in the figure below:
CV9202L-T
The MainBoard CV9202L-T uses the SPV9202BD processor, W6310GKB-12 RAM, and SPI FLASH 8Mb ROM.
It is advisable to begin repairing the motherboard by checking all voltage converters and linear stabilizers necessary to provide power to the nodes and chips in the operating and standby modes. The processor core is powered by + 1V. Also, for operation of the SPV9202BD, voltages + 2.5V and + 3.3V are required. Check the power of the LCD panel (depending on the type, + 5V or + 12V), it is convenient to measure directly on the LVDS connector. If the TV does not exit Stand-by mode, if it has the necessary power supply voltages, does not respond to the Remote Control and control buttons, the SPI Flash 25Q64 firmware should be updated.
CV9202L-T can be used in TVs:
AIWA 24LE7020 (Panel V236BJ1-P01), BBK 22LEM-1006/FT2C (Panel M215HTN01.1 KM215N19-AU-01), DEXP 19A3100 (Panel CX185LEDM), DEXP 22A7100 (Panel T215HVN01.0 M215HVN01.0), FUSION FLTV-24T22 (Panel M236HGE-P02), FUSION FLTV-22T22 (Panel 720p HD 1366x768), SHIVAKI STV-24LED14 (Panel V236BJ1-P01 / CX236LEDM), SUPRA STV-LC24T410FL (Panel M236HGE-P01), SUPRA STV-LC19T410WL (Panel HK185WLEDM CH25H), SUPRA STV-LC22T410FL (Panel LC215DT5A), SUPRA STV-LC24T410WL (Panel HK236WLEDM-CH24H), SUPRA STV-LC19T880WL (Panel LC185TT7A).
The appearance of the power supply
Main features of the DEXP 22A7100 device:
Installed matrix (LED-panel) T215HVN01.0 M215HVN01.0.
The matrix control uses the Timing Controller (T-CON) M215HVN01.0.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the OB3350CP PWM controller. As power elements of the LED driver, keys of the AOD450 type are used.
The necessary supply voltages for all nodes of the DEXP 22A7100 TV are generated by the MP24S-CX power module or its analogs using OB2273 microcircuits (PWM SOT23-6).
MainBoard - the main board (motherboard) is a CV9202L-T module using Cpu: SPV9202BD, DDRAM: W6310GKB-12, Spi Flash: 25Q64, SOUND: YD1517 and others.
The ST03WS-2A-E tuner provides TV reception and channel tuning.
DEXP 22A7100 TV with T215HVN01.0 LCD, 22 "(56 cm) diagonal size of 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 3000: 1. This model uses a panel with the end position of the backlight LEDs - Edge 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). Input high-frequency or video signal decoded in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i. Supported media file formats: MP3, 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), component, SCART, VGA, HDMI, 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. A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: with stand 503x342x174 mm, without stand 503x314x50 mm.
TV mass: with stand: 3 kg, without stand: 2.75 kg.
Attention! The T215HVN01.0 M215HVN01.0 panel of the DEXP 22A7100 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.