Saturday 18 April 2020

REPAIR / SERVICING TV DEXP F22B7100EE

Technical description and composition of the DEXP F22B7100EE TV, panel type and applicable modules. The composition of the modules.
DEXP LED
Model: F22B7100EE / B
Chassis / Version: CV9202L-T
Panel: CX215LEDM
LED driver (backlight): integrated into PSU
PWM LED driver: OB3350CP
MOSFET LED driver: AOD450
Power Supply (PSU): MP24S-CX
PWM Power: OB2273
MOSFET Power: TO-220
MainBoard: CV9202L-T
IC MainBoard: CPU: SPV9202BD, Spi Flash: 25Q64, DDRAM: W6310GKB-12, SOUND: YD1517
Tuner: ST03WS-2A-E
Technical Specifications F22B7100EE
DEXP F22B7100EE
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP F22B7100EE TV does not turn on at all. The control lights do not light or flash. The TV on the remote control and the control panel buttons do not respond.
In some of these cases, a fault is detected in the MP24S-CX power supply module. It is necessary to measure its secondary output voltages, and in case of their absence, check the power switches (TO-220) and rectifier diodes in the converters for a short circuit.
In case of breakdowns of diodes in the secondary circuits, the converter can operate in emergency short circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key usually 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. OB2273 PWM controllers, in the absence of visible damage or explicit 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, the channels are switched. In some cases, the image appears when you turn on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. Usually the cause of the malfunction is in the breakage of the LEDs, or in the connectors of the LED strips, but sometimes the LED driver also turns out to be faulty.
To detect a break in the LED lines without disassembling the panel, a current source is required. It is impossible to open transitions connected in series with a simple multimeter; voltage of several tens of volts is necessary.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
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). When repairing an MB board, you need to check its CPU components: SPV9202BD, Spi Flash: 25Q64, DDRAM: W6310GKB-12, SOUND: YD1517. Defective items should be replaced. If chips with BGA soldering technology are used, a problem in its implementation is detected by the local heating of the chip.
Before changing the ST03WS-2A-E tuner, if it is not possible to tune to television channels, make sure that there are supply voltages that must be measured at the corresponding tuner pins and checked for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
TV users and owners must remember that attempts to self-repair a DEXP F22B7100EE TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!


FIRMWARE FOR SPI FLASH  ----------->   DEXP F22B7100EE/B, Main: CV9202L-T, Panel: CX215LEDM



 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 supply voltage, 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 F22B7100EE device:
Installed matrix (LED-panel) CX215LEDM.
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 F22B7100EE TV are generated by the MP24S-CX power module or its analogs using OB2273 microcircuits and TO-220 type power switches.
MainBoard - the main board (motherboard) is a CV9202L-T module using CPU chips: SPV9202BD, Spi Flash: 25Q64, DDRAM: W6310GKB-12, SOUND: YD1517 and others.
The ST03WS-2A-E tuner provides TV reception and channel tuning.
DEXP F22B7100EE TV with a CX215LEDM LCD display, diagonal size 22 "(56 cm) 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 3000: 1. In this The model uses a panel with the end-face positioning 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 a graphic resolution according to the standard 1080p (Full HD). Input high-frequency or video signal decoded into analog PAL system, SECAM, NTSC Image processing and the formation of the digital signal is in 480i standards, 480p, 576i, 576p, 720p, 1080i, 1080p Supported multimedia file formats:.. MP3, WMA, MPEG4, 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), AV, audio x2, 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, 1920x1080. 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 CX215LEDM panel of a DEXP F22B7100EE 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.