Technical description and composition of the PHILIPS 43PFT4001 TV, type of panel and applicable modules. The composition of the modules.PHILIPS LED
Model: 43PFT4001 / 60
Chassis / Version: MSD3463-T8C1
Panel: K430WD9
LED backlight: 4708-K420WD-A3213K01
T-CON: 6870C-0532A
LED driver (backlight): integrated into MainBoard
PWM LED driver: MP3394S
MOSFET LED driver: AOD256
Power Supply (PSU): integrated into MainBoard
PWM Power: OB5269CP
MOSFET Power: 10N65
MainBoard: MSD3463-T8C1
IC MainBoard: MSD3463-T8C, MX25L6406, TPA3110D2, NXP18275, 29FIQ08ABAEA
Tuner: NoName
Specifications 43PFT4001
PHILIPS 43PFT4001
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The PHILIPS 43PFT4001 TV does not turn on and does not show any signs of operability at all. There is no reaction to the remote control and control buttons from the front panel.
First of all, in such cases, you should verify the operability of the common switching power supply (IIP) - AC / DC voltage converter of the mains voltage. All source elements in this TV model are located on the MainBoard MSD3463-T8C1 main board. It is necessary to measure its output voltages, and in case of their absence (full or partial), it is necessary to check the serviceability of power switches (10N65) of converters and rectifier diodes for the presence of a possible short circuit.
In case of breakdowns of semiconductors in the secondary circuits, the converter can usually work abnormally in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. These can be circuits supplying the PWM controller, damping or frequency-setting circuits, or elements of OOS (negative feedback) in the stabilization circuit. PWM controllers (PWM) OB5269CP, in the absence of external damage and short circuit between the terminals, are checked by replacing with obviously good ones.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
Usually in such cases, a malfunction is detected in the backlight nodes of the LED panel. The reason can be both in the power supply of the LEDs, in their serviceability (breakdown or breakage), as well as in the violation of the contact connections of the LED strips.
It is impossible to check the LED line for breaks 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 will be required, and ideally, a current source. Having disassembled the panel, it is necessary to check each LED separately. Chinese multimeters, as a rule, light up a single 3-volt 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 a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The TV does not turn on, does not respond to the remote control. The indicator blinks or signals standby mode.
Repair or diagnostics of the MSD3463-T8C1 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). Complex repair of MB (SSB) is possible only in the conditions of a service center with the necessary equipment. Checking or replacing elements MSD3463-T8C, MX25L6406, TPA3110D2, NXP18275, 29FIQ08ABAEA requires the necessary training and professional skills to repair modules at the component level. Problems associated with the use of BGA soldering technologies can sometimes be diagnosed by warming up.
In cases where there is no tuning to the channels of on-air or cable television, you should make sure that the software is correct, as well as in accordance with the ratings of the supply voltage at the terminals of the NoName tuner. It is also necessary to check the presence of pulses of data exchange between the tuner and the processor via the I2C bus using an oscilloscope.
Once again, we remind TV users: you should not make attempts to repair it yourself without the appropriate knowledge, experience and the necessary qualifications! Entrust repair to professionals with sufficient experience in the field of repair of electronic equipment.
Service manual and schematic diagram PHILIPS 32PHT4001/60, 43PFT4001/60
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 LED drivers with the MP3394S (MP3394) controller, increase the resistance of the resistor from pin 6 (ISET) to the chassis. The maximum current in each channel (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 790 * 1.23V / (Rset + 0.4).
Repair MainBoard
The appearance of the MainBoard MSD3463-T8C1 is shown in the figure below:
MSD3463-T8C1
MSD3463-T8C1 can be used in TVs:
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 PHILIPS 43PFT4001 device:
Installed matrix (LED-panel) K430WD9.
The matrix control uses the Timing Controller (T-CON) 6870C-0532A.
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 10N65 power switches.
MainBoard - the main board (motherboard) is an MSD3463-T8C1 module, using microchips MSD3463-T8C, MX25L6406, TPA3110D2, NXP18275, 29FIQ08ABAEA and others.
The NoName tuner provides television reception and channel tuning.