TELEFUNKEN LEDModel: TF-LED32S35T2
Chassis / Version: MSD3463-T8C1
Panel: K320WD5
LED backlight: 4708-K320WD-A4213K01
T-CON: 32-37 R0W2.1 HD VER 0.1 6870C-0442B // LC320DXJ-SGE1 / SGK1, P / N 6870S-1578C
LED driver (backlight): integrated in MainBoard
PWM LED driver: MP3394S
MOSFET LED driver: AOD256
Power supply (PSU): integrated into the MainBoard
PWM power: OB5269CP
MOSFET power: AOTF10N65
Main board: MSD3463-T8C1 // MSD6308-T8C2
IC motherboard: MSD3463-T8C, MX25L6406, TPA3110D2, NXP18275, 29FIQ08ABAEA
Control: IR: 4707-48L51F-A52A4F01
TELEFUNKEN TF-LED32S35T2
General Repair Instructions for LCD LCD TVs
Possible malfunctions
- The TELEFUNKEN TF-LED32S35T2 television does not switch on and shows no sign of switching on. There is no reaction to the control buttons or the remote control.
Malfunction in such cases should be looked for in the elements of the power source - the AC / DC converter, which is located on the main board MSD3463-T8C1 of the MainBoard. It is necessary to measure its secondary output voltages and, if these are not present, to check the operating state of the power switches of the converters and the rectifying diodes in order to detect any short-circuit.
In the event of a failure of the secondary circuits, the converter can operate in emergency short-circuit mode and during a short-circuit in the power elements of the primary circuit, the main fuse generally breaks.
Mos-Fet keys used in switch mode power supplies generally fail due to a malfunction of other elements likely to put it out of service in key mode or to cause an excess of current or maximum voltage. This can be a power supply, damper circuits or OOS stabilization elements (negative reaction). The reason for the power button failure may be PWM IC_Power. It is checked only by replacement with a known product.
- There is no picture, there is sound, it responds to the remote control. Or, the image may appear for one second when it is turned on and immediately disappear.
Usually, in such cases, a malfunction is detected in the backlight nodes of the LED panel. This can be due to both the power supply of the LEDs, their operating state (failure or breakage) and the violation of the contact connections of the LED strips.
To check the LED lines for breaks without dismantling the panel, for example, a power source will help you. It is impossible to open PN junctions connected in series with a simple multimeter, a voltage of the order of several tens of volts is required.
- The indicator blinks or stays on continuously, the TV does not turn on, does not respond to the remote control.
Repairing or diagnosing the MSD3463-T8C1 motherboard should start 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 it is not possible to replace the MB (SSB) card, you should check the condition of its components - MSD3463-T8C, MX25L6406, TPA3110D2. Defective components must be replaced.
Again, remind users! Any attempt to repair the TELEFUNKEN TF-LED32S35T2 independently without the appropriate qualifications and experience may lead to its non-repair.
FIRMWARE SPI FLASH -----------> TELEFUNKEN TF-LED32S35T2, Main: MSD3463-T8C
TV LED IC MP3394/MPS3394S LED Driver Diagnostics Throubleshooting
The earlier MP3394 was replaced by MPS3394S, which is an upgraded version of the same IC, and found in the 17IPS20 power supply board. It is the main heart of the backlighting LED drive and the failure of this IC can cause the TV not to start. This is a voltage step-up IC that takes 5-V to 28-V at its input pin 15 (Vin) and raises it to drive four independent strings of LEDs. It also performs other functions such as voltage regulation between the LED strings, and provides a dimming facility using pulse-width modulation (PWM). An important aspect of this IC is that it has built-in open and short LED protection circuitry. It is also able to sense the current and voltage of the LED matrix load and determine abnormal conditions. That means that if all the LEDs in the matrix go open or short, it will prevent the television from switching ON.
The IC has internal control logic that produces the GATE signal to drive an external MOSFET transistor. This is the transistor that is switched against an inductor to step-up the voltage, and the gate signal is produced only when the internal control logic detects normal conditions. It is able to determine normal/abnormal conditions through internal comparators, and one such is the LED Over-Voltage Protection (LED OVP) comparator that provides Short String Protection (SSP).
When the TV is switched ON, this IC is enabled through pin 2, by a voltage greater than 1.8-V. It first checks the circuit configuration, and then checks the over-voltage protection signal at (pin 12) to determine if the rectifier diode is open and whether the booster MOSFET (driven by the GATE signal) is short to ground. If the OVP voltage at pin 12 is lower than 70-mV (may be different for other board versions), then it disables itself and the TV will not start.
On the 17IPS20 board, the GATE signal is known as GATE_LED, which drives a bi-polar junction transistor (BJT) Q500 (BC858B). This transistor then drives Q502/Q503 MOSFET booster group of transistors to step-up the voltage (shown in the following pages of this article). In this circuit configuration the inductance coils are L500 and L501. The high voltage produced then goes into a group of rectifier diodes D503 and D504 producing a positive DC voltage for the LEDs. The over voltage protection signal is known as OVP_LED. Whilst all the LED strings take their power from this positive voltage source, they all have separate independent drain pins through the MPS3394S controller IC.
There are also other parameters to consider such as Under-Voltage Lock-Out (UVLO), which is determined by measuring the rising-edge of Vin. This parameter has to be between 3.5-V and 4.4-V, with 3.9-V being the typical value. It is a very clever IC as it can also detect open and short LED strings in the backlight array.
Although this diagnostic cannot tell you the condition of each individual diode, it can indicate the condition of each string of diodes in the backlight matrix. The MPS3394S IC (SOIC16 package) drives four separate strings of LEDs through dedicated open drain output pins. LED string 1 is driven by pin 11, LED string 2 by pin 10, LED string 3 by pin 9, and LED string 4 by pin 8. It also monitors the voltages at these pins so that if there was a shorted LED in one of the strings then it would disconnect that string. If the voltage at any of these pins is greater than 6.1-V, then this condition triggers the short circuit protection mechanism for disconnecting the string at that pin. It is also possible to determine an open string, and in this case, this condition is detected when the pin voltage is lower than 196-mV.
Interestingly, this IC is designed such that it will always try to light at least one string if it is working. The only time when the step-up converter shuts-down completely is if all the strings were either open, or short. Therefore, before you rush off to eBay to buy a new chip, measure the voltages at these pins to make sure that the diodes are not faulty. Otherwise, you will end up wasting a lot of time and money!
To reduce the backlight current in the LED drivers with the MP3394S controller (MP3394), increase the resistance of the pin 6 resistance (ISET) to the chassis. The maximum current in each channel (in milliamps) for the resistance Rset (in kilo-ohms) is determined from the ratio 790 * 1.23 V / (Rset + 0.4).Main board repair
The appearance of the MainBoard MSD3463-T8C1 is illustrated in the figure below:
MSD3463-T8C1
The MSD3463-T8C1 can be used in televisions:
PHILIPS 32PHT4001/60 (Panel K320WD92), PHILIPS 43PFT4001/60 (Panel K430WD9), TELEFUNKEN TF-LED39S35T2 (Panel K390WD5 K390WD5UB280H200), TELEFUNKEN TF-LED32S35T2 (Panel K320WD5).
Main features of the TELEFUNKEN TF-LED32S35T2 device:
Installed matrix (LED-panel) K320WD5.
The matrix control uses the Timing Controller (T-CON) 32-37.
To power the backlight LEDs, a converter is used, combined with the main board MSD3463-T8C1, controlled by the MP3394S PWM controller. As the power elements of the LED driver, keys of the AOD256 type are used.
The power module is combined with the MainBoard and is made according to the scheme of a flyback AC / DC voltage converter using OB5269CP microcircuits and power switches of the AOTF10N65 type.
MainBoard - the main board (motherboard) is an MSD3463-T8C1 module, using microchips MSD3463-T8C, MX25L6406, TPA3110D2, NXP18275, 29FIQ08ABAEA and others.
