Saturday 21 March 2020

REPAIR / SERVICING TV BBK 22LEM-1004

Technical description and composition of the TV BBK 22LEM-1004, type of panel and applicable modules. The composition of the modules.
BBK LED
Model: 22LEM-1004 / FT2C
Chassis / Version: JUC7.820.00085101
Panel: C215X14-E2-P (G2)
LED backlight: Edge LED
PWM LED driver: RT8573GS
MOSFET LED driver: 18N25
Power Supply (PSU): PW52057C
PWM Power: LD7750RGR
MOSFET Power: KF4N65F
MainBoard: JUC7.820.00085101
IC MainBoard: CPU: Mstar MSB101A, SPI FLASH GD25Q64BS, DRAM: H5TQ1G63EFR, Sound: YD1517P
Tuner: DT21 WN-2A-E
Technical Specifications 22LEM-1004 / FT2
BBK 22LEM-1004
General repair guidelines for TV LCD LED
Possible malfunctions
- BBK 22LEM-1004 does not turn on and does not show any signs of performance at all. Does not blink indicators and does not respond to control buttons.
In such cases, the PW52057C power supply is usually faulty. It is necessary to measure its secondary output voltages, and if they are absent, check the power switches (KF4N65F) and rectifier diodes in the converters for 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 controllers LD7750RGR, in the absence of visible damage or frank fault between the terminals, are checked by replacing with new, or obviously working.
- There is no image, but there is sound and all the other functions of the TV work. The image sometimes for a second appears immediately after turning on and disappears.
The faulty usually in these cases is the backlight matrix (LED-panel). 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.
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 JUC7.820.00085101 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 CPU elements: Mstar MSB101A, SPI FLASH GD25Q64BS, DRAM: H5TQ1G63EFR, Sound: YD1517P 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 the TV works normally from external devices, but does not tune into television channels, the tuner DT21 WN-2A-E may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding conclusions. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
TV users and owners must remember that attempts to self-repair a BBK 22LEM-1004 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!

FIRMWARE FOR SPI FLASH  ----------->   BBK 22LEM-1004/FT2C, Main: JUC7.820.00085101, Panel: C215X14-E2-P (G2)


 The appearance of the MainBoard JUC7.820.00085101 is shown in the figure below:
JUC7.820.00085101
JUC7.820.00085101 can be used in TVs:
BBK 22LEM-3082/FT2C (Panel C215X14-E2-P(G2)), BBK 24LEM-1004/T2C (Panel C236X13-E4-C(G2), BBK 19LEM-1004/T2C (Panel C185X14-E3-P (G2)), BBK 19LEM-1001/T2C (Panel M185X12-E1-P (G4) ), ROLSEN RL-19E1308T2C (Panel C185X14-E3-P(G2)), ROLSEN RL-22E1308FT2C (Panel C215X14-E2-P(G2)), ROLSEN RL-24E1302T2C (Panel C236X13-E2-C (G2) ).
The appearance of the power supply
Main features of the BBK 22LEM-1004 device:
Installed matrix (LED-panel) C215X14-E2-P (G2).
A converter controlled by the RT8573GS PWM controller is used to power the backlight LEDs. As power elements of the LED driver, keys of the 18N25 type are used.
The necessary supply voltages for all nodes of the TV BBK 22LEM-1004 are generated by the PW52057C power module or its analogs using LD7750RGR microcircuits and KF4N65F type power switches.
MainBoard - the main board (motherboard) is a JUC7.820.00085101 module, using CPU chips: Mstar MSB101A, SPI FLASH GD25Q64BS, DRAM: H5TQ1G63EFR, Sound: YD1517P and others.
The DT21 WN-2A-E tuner provides television reception and channel tuning.