Monday 10 August 2020

REPAIRING / SERVICING TV TELEFUNKEN TF-LED32S66T2S

Technical description and composition of the TELEFUNKEN TF-LED32S66T2S TV, panel type and modules used. The composition of the modules.
TELEFUNKEN LED
Model: TF-LED32S66T2S
Chassis / Version: CV338H-T42
Panel: CX315DLEDM
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
MOSFET Power: N-FET TO-252
MainBoard: CV338H-T42
IC MainBoard: CPU: MSD6A338, SPI Flash: W25Q16, MSB102KT, KLM4G1FEPD, MP7752
Tuner: CDT-9NT372RF-10 (R842)
TF-LED32S66T2S Specifications
TELEFUNKEN TF-LED32S66T2S
General recommendations for TV LCD LED repair
Possible manifestations of malfunctions
- TELEFUNKEN TF-LED32S66T2S does not turn on, does not respond to buttons and the remote control, indicators on the front panel do not light or flash.
In such cases, the AC / DC converter of the mains voltage, which is combined with the CV338H-T42 main board, is often faulty. Its output voltages should be measured, and in their absence, check the serviceability of the power switches (N-FET TO-252) of the converters and rectifier diodes for the probability of a short circuit.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in an emergency mode of short circuit without output voltages, and with a short circuit in the elements of the primary circuit, the mains fuse most often breaks off immediately and, less often, the current sensor in the source of the key.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can disable it in the key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying the PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) PWM SOT23-6, in the absence of external damage and a short circuit between the terminals, are checked by replacing them with a known good one.
- There is no picture, but there is sound and reaction to the remote control. Or the image may appear for a second immediately after switching on.
Usually, in such cases, a malfunction is detected in the nodes of the backlight of the LED panel. The reason can be found in the malfunction of the LEDs, in the violation of the contact connections of the LED strips, or in the provision of their power supply (LED driver).
It is impossible to check the LED bars for a break without disassembling the panel with a multimeter or tester. For these purposes, it is necessary to open all series-connected PN junctions and a voltage of the order of tens of volts is required, and ideally a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters tend to light a single 3V LED in the forward direction. In the case of using dual 6-volt LEDs, the PN junction of its protective zener diode can serve as an indicator of serviceability. In faulty LEDs, the zener diode will either be cut off, or pierced in the K / Z.
- The TV does not go into operation, does not respond to the remote control. The indicator on the front panel is on or blinking.
Repair or diagnostics of the CV338H-T42 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 attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - CPU: MSD6A338, SPI Flash: W25Q16, MSB102KT, KLM4G1FEPD, MP7752 which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (indicated by warming up).
Before changing the tuner CDT-9NT372RF-10 (R842), if it is not possible to tune to television channels, you should make sure that there are supply voltages, which must 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 monitored with an oscilloscope
Attention! Users and owners of TF-LED32S66T2S TVs who do not have the appropriate qualifications, knowledge and experience are strongly discouraged from trying to repair themselves in order to avoid negative consequences that can lead to the complete non-repairability of the device.

DOWNLOAD SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> Chassis CV338H-T42-13B



https://4.bp.blogspot.com/-pIusptWH-FU/XyQaGXFAzzI/AAAAAAABCjE/FDPBJ2pNwkYpvBLotgCeoFg_SKC7mUJLACK4BGAYYCw/s1600/CV338H-T42_DCE.jpg The appearance of the MainBoard CV338H-T42 is shown in the figure below:
CV338H-T42
CV338H-T42 can be used in TVs:
BBK 32LEX-5023/T2C (Panel V320BJ6-Q01 Rev.C1 (TH32YS1705C0327)), BBK 32LEX-5024/T2C (Panel TH32YS1704D0089).
Main features of the TELEFUNKEN TF-LED32S66T2S device:
Installed matrix (LED panel) CX315DLEDM.
To power the backlight LEDs, a converter combined with the CV338H-T42 main board is used, controlled by the BIT3267 PWM controller. The keys of the AOD4454 type are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter circuit using PWM SOT23-6 chips and N-FET TO-252 power switches.
MainBoard - the main board (motherboard) is a CV338H-T42 module, using CPU chips: MSD6A338, SPI Flash: W25Q16, MSB102KT, KLM4G1FEPD, MP7752 and others.
Tuner CDT-9NT372RF-10 (R842) provides reception of television programs and tuning to channels.
TV TELEFUNKEN TF-LED32S66T2S with LCD, diagonal size 31.5 "(80 cm) 16: 9. The brightness of the screen is 250 cd / m² provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 2400: 1. This TV model uses LED backlighting technology to display high quality HD images at a resolution of 1366x768 pixels in 720p (HD Ready).
TF-LED32S66T2S TV has built-in SMART software and pre-installed Android operating system. Internet connection can be made via Wi-Fi wireless connection. Supported media file formats: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI, USB, Ethernet (RJ-45), Wi-Fi 802.11n. A headphone output is provided.
The digital tuner is capable of receiving TV channels in the DVB-T MPEG4, DVB-C, DVB-T2 standards.
TV weight: 3.5 kg.
Attention! Panel LED TV TELEFUNKEN TF-LED32S66T2S 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.