Wednesday 25 March 2020

REPAIR / SERVICING TV BBK LEM3248SD

Technical description and composition of the BBK LEM3248SD TV, panel type and applicable modules. The composition of the modules.
BBK LED
Model: LEM3248SD
Panel: HV320WX2-130 (B3) // HV320WX2-120
LED driver (backlight): TV3232-ZC02 M01B3142803
PWM LED driver: AP3608EM-G1 (20), AP3039AM-G1 (14)
MOSFET LED driver: B6010D
Power Supply (PSU): TV3207-ZC02-01 (C) KB-5150 ICE3B0S657
PWM Power: OB2263, ICE3B0565 (Standby)
MOSFET Power: FDPF7N65, AO4435
MainBoard: MSTV3208-ZC01-01 8C4H007AMT31545
IC MainBoard: CPU: MST6M48RHS-LF-Z1; SPI Flash: MX25L3206E; Sound: TDA1517P
Tuner: F21WT-3BAR-E
Control: RC3229
Technical Specifications LEM3248SD
BBK LEM3248SD
General repair guidelines for TV LCD LED
Possible malfunctions
- The BBK LEM3248SD TV does not turn on, does not respond to the remote control and the control panel buttons, does not blink with any indicators.
With such manifestations, a malfunction is most likely to be detected in the TV3207-ZC02-01 power supply module. It is necessary to measure its secondary output voltages, and if they are absent, check the operability of the power switches (FDPF7N65, AO4435) of the converters and rectifier diodes for a short circuit.
In case of breakdowns in the secondary circuits, the converter can operate in a short circuit mode, and during a short circuit in the elements of the primary circuit, the mains fuse usually breaks.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, power supply, frequency-setting, damper ... as well as elements of the Negative Stabilization Feedback. The PWM microchip (PWM) OB2263, ICE3B0565 (Standby) can also cause a malfunction of the power switch of the converter and is checked by replacement.
- There is no image, there is sound, it reacts to the remote control, channels are switched. In some cases, the image appears when you turn on and immediately disappears.
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.
When diagnosing, it is necessary to take into account that it is impossible to check the open in the chain of LED lines without disassembling the panels using a tester or multimeter. To open all PN junctions connected in series, a voltage of the order of several tens of volts is required, and ideally, a current source. By opening the panel, each LED can be checked separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect probes in the forward direction to it. In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, the indicator indicates standby or operating mode, or blinks.
Repair or diagnostics of the 8C4H007AMT31545 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, update or replace the software (software).
TV users and owners need to remember that attempts to self-repair a BBK LEM3248SD TV without proper qualifications and necessary experience can lead to serious negative consequences!
Schematic Diagrams 7 pages 2009 on model LEM2649HD, LEM3248SD



SCHEMATIC DIAGRAM    ------------------>   Power supply circuit TV3207-ZC02-01

 To reduce the backlight current in LED drivers with the AP3039AM controller and the AP3608EM terminal stage (AP3039AM-G1 & AP3608EM-G1), the AP3608EM (AP3608E) microcircuit should proportionally increase the resistor from terminal 14 (ISET) to the housing. The maximum current in each channel (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 1.194V / Rset. In channels connected in parallel, the currents add up.

Repair MainBoard
The appearance of the MainBoard MSTV3208-ZC01-01 is shown in the figure below:
The motherboard MSTV3208-ZC01-01 is made using the multifunction microprocessor MST6M48RHS-LF, which includes a scaler (graphic controller-scaler). To organize the work of the processor, the external RAM H5PS5162GFR 512Mb DDR2 SDRAM in BGA version and SPI FLASH 25Q32 (4Mb) are used. To provide power to the processor core, a DC / DC converter with an output voltage of 1.2V is used, assembled on the basis of the MP1482 PWM controller. Other nodes of the processor are powered by linear voltage stabilizers 2.5V, 3.3V. 1.8V voltage is used to power the DDR RAM, 3.3V is needed for the SPI FLASH ROM.
It is advisable to start the MainBoard repair by checking the supply voltage in Stand-by mode 5V and 3.3V. In operating mode, check the operation of all linear stabilizers and the DC / DC converter. If there is a backlight and there is no image, you need to check the power of the 5V or 12V panel (depending on the type of LCD panel), which should be present directly on the LVDS connector.
If the indicator signals Stand-by mode and does not respond to the remote control and control buttons, it is recommended to update the SPI Flash software. Taking into account the glitchiness of Winbond SPI chips, it is advisable to replace them with new ones in case of software failures.
MSTV3208-ZC01-01 can be used in TVs:
BBK LEM2648SD (Panel V260B1-LE9 revC1), BBK LEM3248SD (Panel HV320WX2-130 (B3)), BBK LMP3229HDU Ver1 (Panel T315HW02 v.7), BBK LMP3229HDU Ver2 (Panel T315HW04 V7), BBK LEM2649HD (Panel V260H1-LE7 Rev C1), MYSTERY MTV-2607W (Panel V260H1-L05), MYSTERY MTV-3206 (Panel T315XW04 V.7), MYSTERY MTV-3207W (Panel V315B3-L04 rev.c1), MYSTERY MTV-3213LW (Panel T315XW04 V.8), MYSTERY MTV-2220LW (Panel CLAA215FA15), MYSTERY MTV-3207W (Panel HV320WX2-110), MYSTERY MTV-2614LW (Panel V260H1-LE6), MYSTERY MTV-3208WH (Panel V315H1-L02), MYSTERY MTV-2411LW (Panel V236H1-LE5 Rev.C1), MYSTERY MTV-2618LW (Panel V260B2-LE11), MYSTERY MTV-2211LW (Panel CLAA215FA10), MYSTERY MTV-2414LW (Panel V236H1-L01), MYSTERY MTV-2611LW (Panel V260H1-LE6 Rev.C1), MYSTERY MTV-3206W (Panel T315XW03 V.3), MYSTERY MTV-3211LW (Panel V315H3-LE2 Rev. C1), MYSTERY MTV-4207WH (Panel T420HW09 V.1), MYSTERY MTV-1921LD (Panel HT185WX3).
The appearance of the power supply
Main features of the BBK LEM3248SD device:
Installed matrix (LED-panel) HV320WX2-130 (B3) or HV320WX2-120.
The LED driver TV3232-ZC02 is used to power the backlight LEDs, it is controlled by the AP3608EM-G1 (20), AP3039AM-G1 (14) PWM controller. As power elements of the LED driver, keys of the type B6010D are used.
The necessary supply voltages for all nodes of the TV BBK LEM3248SD are generated by the TV3207-ZC02-01 power supply module or its analogs using OB2263, ICE3B0565 (Standby) microcircuits and power switches of the FDPF7N65, AO4435 type.
MainBoard - the main board (motherboard) is an MSTV3208-ZC01-01 module, using CPU chips: MST6M48RHS-LF-Z1; SPI Flash: MX25L3206E; Sound: TDA1517P and others.
The F21WT-3BAR-E tuner provides television reception and channel tuning.
 LED TV BBK LEM3248SD with LCD HV320WX2-130, diagonal size 32 "(81 cm) in 16: 9 format. The required brightness of the screen is 450 cd / m² LED backlight LED. The ratio of maximum brightness to minimum (contrast) is 6000 : 1. This model uses side illumination from Edge LEDs. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC Graphically I 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, MKV, JPEG.
The power of the sound system 16 W (2x8 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, component, SCART, RGB, VGA, HDMI x2, USB. 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, 1360x768.
The power consumed by the TV in the operating mode from the network is 75 watts.
Overall dimensions: With stand 768x540x180 mm, Without stand 768x498x43 mm.
TV Weight: 7.5 kg.
Attention! The HV320WX2-130 (B3) panel of the BBK LEM3248SD 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.