Technical description and composition of the DEXP H20D7100E TV, type of panel and applicable modules. The composition of the modules.DEXP LED
Model: H20D7100E / W
Chassis / Version: CV512L-U24
Panel: T195XVN01.0
LED backlight: Edge LED
T-CON: M195XTN01.0
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3367A
MOSFET LED driver: MMBT3904
Power Supply (PSU): integrated into MainBoard
PWM Power: LD5535
MOSFET Power: 70R900P
MainBoard: CV512L-U24
IC MainBoard: CPU: S2T512, SPI Flash: GD25Q64C, Audio: TDA3118E28
Tuner: CDT-9NT372-RD60 (RDA5160), CDT-9NS13J-RD41 (RDA5815)
Appearance
DEXP H20D7100E
General repair guidelines for TV LCD LED
Possible malfunctions
- The DEXP H20D7100E 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 AC / DC voltage converter, which is combined with the main board CV512L-U24, is often faulty. Then we recommend that you measure its output voltages and, if they are absent, you should check the health of the power switches (70R900P) and the rectifier diodes of the converters for possible short-circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short-circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the main fuse and, less often, the current sensor at the source of the key are most often cut off.
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 circuits (OOS) of stabilization. PWM controllers (PWM) LD5535, 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, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
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 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 CV512L-U24 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). Sometimes they require checking or replacing (if necessary) the elements of the MainBoard - CPU: S2T512, SPI Flash: GD25Q64C, Audio: TDA3118E28. In cases where the BGA processor is used, its malfunction is usually detected by local heating.
In cases where there is no tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the tuner CDT-9NT372-RD60 (RDA5160), CDT-9NS13J-RD41 (RDA5815). It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> Main CV512L-U24
FIRMWARE FOR SPI FLASH -----------> DEXP H20D7100E/W, Main: CV512L-U24, Panel: T195XVN01.0
The appearance of the MainBoard CV512L-U24 is shown in the figure below:Cultraview CV512L-U24
Key Features of the DEXP H20D7100E:
Installed matrix (LED-panel) T195XVN01.0.
The matrix control uses the Timing Controller (T-CON) M195XTN01.0.
To power the backlight LEDs, a converter is used, combined with the main board CV512L-U24, controlled by the BIT3367A PWM controller. As power elements of the LED driver, keys of the type MMBT3904 are used.
The power module is combined with the MainBoard and is made according to the scheme of a flyback AC / DC voltage converter using LD5535 microcircuits and power switches of the type 70R900P.
MainBoard - the main board (motherboard) is a CV512L-U24 module, using CPU chips: S2T512, SPI Flash: GD25Q64C, Audio: TDA3118E28 and others.
The tuner CDT-9NT372-RD60 (RDA5160), CDT-9NS13J-RD41 (RDA5815) provides the reception of television programs and tuning to channels.