Wednesday 18 December 2019

REPAIRING / SERVICING TV TELEFUNKEN TF-LED39S6

Technical description and composition of the TELEFUNKEN TF-LED39S6 TV, type of panel and applicable modules. The composition of the modules.
TELEFUNKEN LED
Model: TF-LED39S6 TF-LED39S6T2S
Chassis / Version: CV338H-T42
Panel: T390XVN01.0
LED driver (backlight): integrated into MainBoard
PWM LED driver: BIT3267
MOSFET LED driver: AOD4454
Power Supply (PSU): integrated into MainBoard
PWM Power: PF6000AG (PWM SOT23-6)
MainBoard: CV338H-T42
IC MainBoard: MSD6A338, MSB102KT, W25Q16DVSSIG, THGBM8G5D1KBAIL
Tuner: CDT-9NT372RF-10 (R842)
Technical Specifications TF-LED39S62T2
TELEFUNKEN TF-LED39S6
General repair guidelines for TV LCD LED
Possible malfunctions
- TELEFUNKEN TF-LED39S6 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 AC / DC voltage converter is often faulty, which is combined with the CV338H-T42 main board. It is necessary to measure its output supply voltages, and in case of their absence, check the serviceability of the power switches of the converters and rectifier diodes for the probability of breakdown in PN semiconductor junctions.
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. PF6000AG PWM controllers (PWM SOT23-6), in the absence of visible damage or open faults between the terminals, are checked by replacing them with new ones, or obviously working ones.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
As a rule, in such cases there is no display backlight. 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 enter the operating mode, does not respond to the remote control. The indicator on the front panel lights constantly or blinks.
Repair or diagnostics of the CV338H-T42 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). If it is not possible to replace the MB (SSB) card, you need to check the health of its elements - MSD6A338, MSB102KT, W25Q16DVSSIG, THGBM8G5D1KBAIL. Defective components should be replaced.
If the TV works normally from external devices, but does not tune into television channels, the tuner CDT-9NT372RF-10 (R842) 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.
Attention TV owners! Self-repair attempts by TELEFUNKEN TF-LED39S6 are not recommended by the manufacturer and can lead to serious negative consequences!

SCHEMATIC diagram ----------------> BBK 32LEX-5024 Chassis CV338H-T42-13B

The appearance of the MainBoard CV338H-T42 is illustrated in the figure below:
CV338H-T42
The CV338H-T42 can be used in televisions:
BBK 32LEX-5023/T2C (Panel V320BJ6-Q01 Rev.C1 (TH32YS1705C0327)), BBK 32LEX-5024/T2C (Panel TH32YS1704D0089).
Main characteristics of the TELEFUNKEN TF-LED39S6 device:
Installed matrix (LED panel) T390XVN01.0.
To supply the backlight LEDs, a converter is used, associated with the CV338H-T42 main board, controlled by a BIT3267 PWM controller. As power elements of the LED driver, keys of type AOD4454 are used.
The power module is combined with the MainBoard and is manufactured in accordance with the AC / DC Flyback voltage conversion circuit using PF6000AG microcircuits (PWM SOT23-6).
MainBoard - the motherboard (motherboard) is a CV338H-T42 module, using the microchips MSD6A338, MSB102KT, W25Q16DVSSIG, THGBM8G5D1KBAIL and others.
The CDT-9NT372RF-10 (R842) tuner can receive TV programs and tune in channels.