Monday 10 August 2020

REPAIRING / SERVICING TV TELEFUNKEN TF-LED28S9T2

Technical description and composition of the TELEFUNKEN TF-LED28S9T2 TV, panel type and modules used. The composition of the modules.
TELEFUNKEN LED
Model: TF-LED28S9T2
Chassis / Version: CV9202H-TPW
Panel: CX275DLEDM
LED backlight: RF-AD280E32-0501S-01
T-CON: MT3151A05-3-XC-1
LED driver (backlight): integrated into PSU
PWM LED driver: OB3350CP
Power Supply (PSU): CVB32005
PWM Power: AP3105NV (PWM SOT23-6)
MainBoard: CV9202H-TPW
IC MainBoard: CPU: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2
Tuner: ST03WS-2A-E
Control: IR: CX-2816-3216-IR VER 1.0
TF-LED28S9T2 Specifications
TELEFUNKEN TF-LED28S9T2
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- TELEFUNKEN TF-LED28S9T2 TV does not turn on at all. Control lamps do not light up or blink. The TV on the remote control and control panel buttons does not respond.
With similar manifestations, a malfunction is most likely found in the CVB32005 power module. It is necessary to make sure that its output voltages are present and, if they are completely absent, check the power switches and rectifier diodes for a possible short circuit.
In case of diode breakdowns in the secondary circuits, the converter can operate in an emergency mode of short circuit without output voltages, and with a short circuit in the power elements of the primary circuit, the mains fuse and / or the current sensor in the source of the key usually breaks off.
Mos-Fet power switches used in switching power supplies sometimes fail due to a malfunction of any other elements that can disable it in the key mode, or create an excess of the maximum permissible key parameters. These can be elements supplying a PWM regulator, frequency setting or damper circuits, or elements of negative feedback in the stabilization circuit. PWM controllers AP3105NV (PWM SOT23-6), in the absence of visible damage or outright short circuits between the terminals, are checked by replacing them with new ones, or known to be working properly.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and disappears immediately
A malfunction is usually in these cases most likely in the backlight units of the display matrix. The reason may be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
When trying to detect a break in the LED lines, it should be borne in mind 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, does not respond to the remote control. The indicator blinks or signals the standby mode.
Repair or diagnostics of the CV9202H-TPW motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of complex MB (SSB) repairs and with the necessary skills and equipment, it may sometimes be necessary to replace its chips CPU: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2 and other possible faulty components ... Malfunctions associated with the use of BGA soldering technologies are usually easily diagnosed by the warm-up method.
The malfunction of the ST03WS-2A-E tuner is established after checking the software and all supply voltages at its terminals. The I2C bus data exchange between the tuner and the processor can be monitored with an oscilloscope.
Owners of the TF-LED28S9T2 TV are recommended to contact only qualified specialists with the necessary work experience for repair! Attempts to repair yourself without the appropriate knowledge and skills can lead to irreversible negative consequences!
Additional MainBoard Repair
The MainBoard CV9202H-TPW is shown in the figure below:
CV9202H-TPW
CV9202H-TPW can be used in TVs:


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AKAI LEA-39J29P (Panel HF390BGA-C1), BBK 32LEM-1001/T2C (Panel CX315DLEDM), DNS M39DM8 (Panel V390HJ1-P02 Rev C1), ERISSON 32LEE17 (Panel 720p HD 1366x768), FUSION FLTV-32T22 (Panel ST3151A05), FUSION FLTV-28T20 (Panel LCM-SM275TK301 (D0306)), FUSION FLTV-28T22 (Panel TH280L321-04), FUSION FLTV-32T23 (Panel ST3151A04-1 / Ver.2.4), FUSION FLTV-32T20 (Panel V320BK1-PS5 Rev.C7), TELEFUNKEN TF-LED40S28T2 (Panel CX400DLEDM), TELEFUNKEN TF-LED29S30T2 (Panel V290BJ1-XC01 CX290DLEDM), TELEFUNKEN TF-LED40S6T2 (Panel CX400DLEDM).
External view of the power supply
Main features of the TELEFUNKEN TF-LED28S9T2 device:
Installed matrix (LED panel) CX275DLEDM.
Matrix control uses Timing Controller (T-CON) MT3151A05-3-XC-1.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by the OB3350CP PWM controller.
The formation of the necessary supply voltages for all nodes of the TELEFUNKEN TF-LED28S9T2 TV is carried out by the CVB32005 power module, or its analogs using AP3105NV microcircuits (PWM SOT23-6).
MainBoard - the main board (motherboard) is a CV9202H-TPW module, using CPU chips: SPV9202BD (1416-D), DRAM: K4B1G1646G-BCKO, SPI FLASH: Winb25Q64FVSIG, AUDIO: TPA3110LD2 and others.
The ST03WS-2A-E tuner provides reception of television programs and tuning to channels.
TELEFUNKEN TF-LED28S9T2 TV with CX275DLEDM LCD, 28 "(71 cm) 16: 9. Brightness of 230 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 3000: 1 The LED panel of this TV is equipped with edge LED backlighting. You can view images in high quality HD at a resolution of 1366x768 pixels in 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM , NTSC Graphic processing and digital signal shaping takes place in the standards 480i, 480p, 576i, 576p, 720p, 1080i Supported multimedia file formats: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG.
Speaker power of 16 W (2x8 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x2, VGA, HDMI x3, USB. A headphone output is provided. To connect a computer or laptop to this TV model, use the VGA (D-Sub 15) connector on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The digital tuner is capable of receiving TV channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
Overall dimensions: 646x439x190 mm.
TV weight: 6 kg.
Attention! Panel CX275DLEDM LED TV TELEFUNKEN TF-LED28S9T2 is an expensive and unreliable element.
Do not allow any impacts on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV non-repairable.