Wednesday 18 December 2019

REPAIRING / SERVICING TV TELEFUNKEN TF-LED32S26T2

TELEFUNKEN LED
Model: TF-LED32S26T2
Chassis / Version: TP.SIS231.PT85
Panel: MT3151A05
LED driver (backlight): integrated in MainBoard
PWM LED driver: OB3350CP
LED MOSFET driver: AOD4454
Power supply (PSU): integrated into the MainBoard
PWM power: PWM SOT23-6
MainBoard: TP.SIS231.PT85
IC MainBoard: CPU: SIS231, DRAM: NT5CB64M16FP-DH, Flash SPI: 25Q64, TPA3110LD2, SI2168, RT7237
TELEFUNKEN TF-LED32S26T2
General Repair Instructions for LCD LCD TVs

Possible manifestations of faults
- The TELEFUNKEN TF-LED32S26T2 television does not switch on at all. The indicator lights do not light up and do not flash. The remote control TV and buttons on the control panel do not respond.
The malfunction in such cases should be looked for in the elements of the power source - the network voltage converter (AC / DC), located on the MainBoard TP.SIS231.PT85 main board. It is necessary to measure its output voltages and, in case of absence, to check the correct operation of the power switches of the converters and the rectifying diodes to determine the probability of a short circuit.
If the secondary circuits fail, the converter can operate in emergency short-circuit mode. During a short circuit in the power elements of the primary circuit, the fuse or the current sensor at the source of the key breaks more often.
The failure of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example in the circuits supplying the PWM controller, frequency regulators or registers, as well as in the circuits of stabilization with negative feedback. PWM controllers (PWM) PWM SOT23-6, if they show no visible damage to the case and they are not short-circuited between the terminals, are generally checked by replacement.

- There is no picture, but there is sound and feedback from the remote control. Or for one second, the image may appear immediately after the power is turned on.
In some cases, a malfunction is due to a lack of backlight. This may be due to a break in the LED circuit or a problem with the stabilization of their power supply.
To check the LED strips, to open all the LED transitions, several tens of volts or more are necessary, it is better to use a current source for these purposes. The rupture of several PN junctions connected in series cannot be detected with a multimeter or a tester. In this case, it is necessary to open the panel and check each indicator. If your multimeter cannot open the LED transitions in direct polarization, you can sometimes detect the presence of a PN junction of the Zener protection diode by connecting the probes in the opposite direction. If the Zener diode is broken or short-circuited, the indicator is defective and must be replaced.

- The indicator blinks or stays on continuously, the TV does not turn on, does not respond to the remote control.
Repairing or diagnosing the TP.SIS231.PT85 motherboard should begin by checking the stabilizers and power converters needed to power the chips and matrix. If necessary, you must update or replace the software (software). If an attempt is made to repair the MB card (SSB), it is necessary to check the status of its elements - CPU: SIS231, NAND: NT5CB64M16FP-DH, SPI Flash: 25Q64, TPA3110LD2, SI2168, RT7237, which may require replacement with new ones. If the BGA processor is installed, it is possible that the solder of the contacts of its conclusions with the card is soldered (it is diagnosed by heating).

Attention TV owners! Self-repair attempts by TELEFUNKEN TF-LED32S26T2 are not recommended by the manufacturer and can lead to serious negative consequences!

FIRMWARE SPI FLASH ---------------->  TELEFUNKEN TF-LED32S26T2, Main: TP.SIS231.PT85, Panel: MT3151A05.

  Schematic diagram Power supply ----------------> Power supply Chassis TP.SIS231.PT85


 The appearance of MainBoard TP.SIS231.PT851 is illustrated in the figure below:
TP.SIS231.PT851
TP.SIS231.PT85 can be used on TVs:
DNS M39DM8 (Panel V390HJ1-P02 Rev C1), DNS S32DC1 (Panel T320XVD01.0), DNS E32D18 (Panel ST3151A05-5 CX315DLEDM), DNS V32D8100S (Panel LSC320HN04-002), ERISSON 40LEP92 (Panel LSC400HN01 G01), ROLSEN RL-39S1502T2C (Panel V390BJ1-L01-D00), RUBIN RB-40D5FT2C (Panel 390HJ5-XCPE1), RUBIN RB-40SE9FT2C (Panel CX400DLEDM), SUPRA STV-LC32T871WL (Panel JHD315GH-E31), SUPRA STV-LC40T871FL (Panel JHD400GF), TELEFUNKEN TF-LED32S26T2 (Panel MT3151A05).


 Main features of the TELEFUNKEN TF-LED32S26T2 device:
Installed matrix (LED panel) MT3151A05.
To power the backlight LEDs, a converter is used, combined with the TP.SIS231.PT85 main board, controlled by the OB3350CP PWM controller. As power elements of the LED driver, keys of the AOD4454 type are used.
The power module is combined with the MainBoard and is made according to the flyback AC / DC voltage converter circuit using PWM SOT23-6 microcircuits.
MainBoard - the main board (motherboard) is a TP.SIS231.PT85 module using CPU chips: SIS231, DRAM: NT5CB64M16FP-DH, SPI Flash: 25Q64, TPA3110LD2, SI2168, RT7237 and others.
Additional technical information about the panel:
Brand: CSOT
Model: MT3151A05-4
Type: a-Si TFT-LCD, Panel
Diagonal size: 31.5 inch
Resolution: 1366x768, WXGA
Display Mode: HVA, Normally Black, Transmissive
Active Area: 697.685x392.256 mm
Surface: Antiglare, Hard coating (3H)
Brightness: 300 cd / m²
Contrast Ratio: 3000: 1
Display Colors: 16.7M (8-bit), CIE1931 62%
Response Time: 6.5 (G to G)
Frequency: 60Hz
Lamp Type: WLED
Signal Interface: LVDS (1 ch, 8-bit)
Voltage: 12.0V