Technical description and composition of the BBK 40LEX-5938 TV, panel type and applicable modules. The composition of the modules.BBK LED
Model: 40LEX-5938 / FT2C
Chassis / Version: CV628H-T42
Panel: CX400DLEDM
LED backlight: CXD400410000-X3
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
MOSFET LED driver: AOD4454
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6 (LD7536)
MOSFET Power: SMK10N60
MainBoard: CV628H-T42
IC MainBoard: CPU: MSD6A628VXM-ST, NAND: KLM4G1FEPD, SPI FLASH: Winb25Q16JVSIQ, AUDIO: TPA3110LD2
Tuner: CDT-9NT372-RF01
Appearance
BBK 40LEX-5938
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK 40LEX-5938 TV does not turn on and does not show any signs of turning on, does not respond to the control buttons or to the remote control.
In such cases, the main power source, the AC / DC voltage converter, which is combined with the MainBoard CV628H-T42, may turn out to be faulty. It is necessary to measure its output supply voltage, and in case of their absence, check the serviceability of the power switches (SMK10N60) of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
In case of breakdowns of semiconductors in 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 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 (LD7536), 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 is responding to the remote control. Or immediately after turning on for a second, the image may appear and immediately disappear.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. The reason may be a break in the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the thong connectors,
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 TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the CV628H-T42 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: MSD6A628VXM-ST, NAND: KLM4G1FEPD, SPI FLASH: Winb25Q16JVSIQ, AUDIO: TPA3110LD2. 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 tuner CDT-9NT372-RF01, if it is not possible to tune to television channels, make sure that there are supply voltages that need to be measured at the corresponding terminals of the tuner and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
It should be remembered! Attempts to independently repair the BBK 40LEX-5938 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
The appearance of the MainBoard CV628H-T42 is shown in the figure below:CV628H-T42
CV628H-T42 can be used in TVs:
BBK 43LEX-5009/FT2C (Panel LC430DUY (SH)(A1)), BBK 40LEX-5025/FT2C (Panel V400HJ6-PE1 DLEDSV400FHD), BBK 32LEX-5027/T2C (Panel V320BJ6-Q01 Rev.C1), SUPRA STV-LC40ST900FL (Panel V400HJ6-PE1).
Main features of the BBK 40LEX-5938 device:
Installed matrix (LED-panel) CX400DLEDM.
To power the backlight LEDs, a converter is used, combined with the main board CV628H-T42, controlled by a BIT3267 PWM controller. As power elements of the LED driver, keys of the AOD4454 type are used.
The power module is combined with the MainBoard and is designed according to the flyback AC / DC voltage converter using PWM SOT23-6 (LD7536) microcircuits and SMK10N60 type power switches.
MainBoard - the main board (motherboard) is a CV628H-T42 module, using CPU chips: MSD6A628VXM-ST, NAND: KLM4G1FEPD, SPI FLASH: Winb25Q16JVSIQ, AUDIO: TPA3110LD2 and others.
The tuner CDT-9NT372-RF01 provides the reception of television programs and tuning to channels.