REPAIR / SERVICING TV BBK LT3223SU

Technical description and composition of the BBK LT3223SU TV, panel type and applicable modules. The composition of the modules.
BBK
Model: LT3223SU
Chassis / Version: ver4.0
Panel: V315B6-P01 HK315TVM-CH14H
T-CON: (12v)
Power Supply (PSU): SIPS32V8
PWM Power: SG3225AN (16), F9222L, L6562A (PFC), LM358 (8), KA3843 (8), LD7535 (PWM SOT23-6)
MOSFET Power: STU446S (3), STU446S (3), JCS83F, JCS2N60F
MainBoard: TM30G V1.0
Tuner: CDT-3FP2I2-01
BBK
Model: LT3223SU
Chassis / Version: Ver2.0
Panel: 32 inch
Inverter (backlight): SIPS32V8 H KB-5150 CEM-1
Trans Inverter: 730-703-SI60-HL TLT-2503 0503
Power Supply (PSU): SIPS32V8 H KB-5150 CEM-1 FORETOP
PWM Power: SG3525AN (16), PWM SOT23-6, L6562A (PFC)
MOSFET Power: STU446S A1189G (3),
MainBoard: TM30G V1.0
Tuner: CDT-3FP2I2-01
Control: RC1902
Technical Specifications LT3223SU
BBK LT3223SU
General recommendations for repairing TV LCD
Possible malfunctions
- The BBK LT3223SU 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 most of these cases, the SIPS32V8 main switching power supply is faulty. It is necessary to measure its secondary output voltages, and in case of their absence, check the serviceability of power switches (STU446S A1189G (3),) of 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 short circuit in the elements of the primary circuit, the mains fuse usually 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. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (PWM) SG3525AN (16), PWM SOT23-6, L6562A (PFC). It is checked only by replacement with a known good one.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
The defect can be caused by problems in the nodes or elements of the backlight of the display, or in the power supply of the lamps or inverter. If all the electrolytic capacitors of the filter according to the power supply of the inverter are working, make sure that the lamps are working, then you need to check the converter keys and the secondary windings of the transformers.
Sometimes, for diagnostic purposes, it is necessary to disable the inverter protection. In such cases, special care must be taken during work, and the protection circuit should be restored immediately after the repair is completed.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the TM30G 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).
Before changing the tuner CDT-3FP2I2-01, 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

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.

PSU Advanced
The LT3223SU model uses a SIPS32V8 power supply unit using the PFC (Power Factor Correction) node - an active filter of the highest harmonics of the current consumption. In fact, it is a boost converter based on the L6562A PWM controller, which eliminates the charge current of the electrolytic capacitor of the rectifier filter directly from the network through open diodes, when its charging current is determined by its reactance.

As a result of the operation of the converter, the envelope of the high-frequency pulses of the input current of the converter will repeat the shape and phase of the input voltage. The health of the PFC node can be indirectly judged by the presence of an increased constant voltage (about + 380V) on the capacitor of the rectifier network

in operating mode.

Main features of the BBK LT3223SU device:
Installed matrix (LCD-panel) 32 inches.
To power the backlight used inverter SIPS32V8. A transformer 730-703-SI60-HL TLT-2503 0503 is installed in the inverter converter.
The necessary supply voltages for all nodes of the BBK LT3223SU TV are generated by the SIPS32V8 power module or its analogs using SG3525AN (16), PWM SOT23-6, L6562A (PFC) microchips and power switches of the STU446S A1189G (3) type.
MainBoard - the main board (motherboard) is a TM30G module.
The tuner CDT-3FP2I2-01 provides the reception of television programs and tuning to channels.

BBK LT3223SU LCD TV with 32 "32" (81 cm) diagonal LCD display in 16: 9 format. 350 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Dynamic contrast ratio of 2500: 1 is achieved by special operation control It is possible to view images in high quality HD at a resolution of 1366x768 pixels in the standard of graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation takes place in . Darth 480i, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats: MP3, JPEG.
The power of the acoustic system of sound 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, component, SCART, RGB, VGA, HDMI x3, 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, 1360x768.
The power consumed by the TV in the operating mode from the network is 180 watts.
Overall dimensions: With stand 802x578x270 mm, Without stand 802x531x100 mm.
Attention! The 32-inch panel of the BBK LT3223SU LCD TV is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!