TELEFUNKEN LEDModel: TF-LED28S19
Chassis / Version: MS306DPS
Panel: LVW280CSOT
T-CON: MT3151A05-5-XC-5 ST2751A01-8
LED driver (backlight): integrated in MainBoard; OUT = 33V
Power supply (PSU): integrated into the MainBoard
PWM power: PWM SOT23-6
Main board: 40-MS306D-MAD2LG MS306DPS
IC MainBoard: SPI FLASH: W25Q32FVSIG
Tuner: XF-3SDT-H
TELEFUNKEN TF-LED28S19
General Repair Instructions for LCD LCD TVs
Possible manifestations of faults
- TELEFUNKEN TF-LED28S19 does not light up, the LEDs on the front panel do not light up and do not flash. The TV does not respond to the control buttons and the remote control.
Malfunction in such cases should be looked for in the elements of the power source - the network voltage converter (AC / DC), located on the main board MainBoard 40-MS306D-MAD2LG. It is necessary to measure the secondary output supply voltages and, if not, check the functionality of the power switches of the converters and the rectifier diodes to determine the probability of failure of the PN semiconductor junctions.
In the event of diode failures in the secondary circuits, the converter can operate in emergency short-circuit mode without output voltages and during a short-circuit in the power elements of the primary circuit, the network fuse and / or the current sensor at the source of the key usually breaks.
Failures of the Mos-Fet keys used in pulsed sources are often caused by malfunctions of other elements, such as power, frequency adjustment, register, etc., as well as by stabilization feedback elements negative. PWM PWM SOT23-6 can also cause the converter power switch to malfunction and is checked for replacement
.
- There is no picture, there is sound, it responds to the remote control, the channels are switched. In some cases, the image appears when you turn it on and immediately disappears.
The most likely in these cases is a malfunction of the LED backlight. This may be due to a break in the LED circuit or a problem with stabilizing their power supply.
When trying to identify a break in the LED lines, you should keep in mind that it is difficult to do so without dismantling the panel. For example, a power source is required to open PN junctions connected in series.
- The television does not enter operating mode, does not respond to the remote control. The indicator on the front panel is permanently on or blinking.
Repairing or diagnosing the 40-MS306D-MAD2LG motherboard should start by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, update or replace the software (software). In some cases, to repair the MB (SSB) card, it may be necessary to replace the - 25Q32 chips with new or obviously good ones. In cases where BGA technologies are used, faults are generally located by the heating method.
If you suspect a malfunction of the XF-3SDT-H tuner, you should first check the accuracy of the software, as well as the presence of the necessary supply voltage levels and pulses of data exchange with the processor via the I2C bus to the corresponding terminals of the tuner.
It must be remembered! Any attempt to repair the TELEFUNKEN TF-LED28S19 independently, in the absence of the required qualifications and experience, is formally discouraged and has negative consequences which may go as far as not fully repairing the device!