Saturday, 14 November 2020

REPAIR / SERVICING TV PHILIPS 39PHT4003

 
Technical description and composition of the PHILIPS 39PHT4003 TV, panel type and modules used. The composition of the modules.
PHILIPS LED
Model: 39PHT4003 / 60
Chassis / Version: KTS18.1E LA
Panel: K390WK9
LED driver (backlight): integrated into MainBoard
PWM LED driver: OB3350CP
MOSFET LED driver: AOD4286
Power Supply (PSU): integrated into MainBoard
PWM Power: LNK6777
MOSFET Power: TO-220
MainBoard: MSD3463-T4C1
IC MainBoard: SPI Flash: MX25L6406E, Audio: TPA3110LD2
Tuner: ST43WS-2A-E
Specifications 39PHT4003
PHILIPS 39PHT4003
General recommendations for TV LCD LED repair
Possible manifestations of defects
- PHILIPS 39PHT4003 does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
A malfunction in such cases should be looked for primarily in the circuit of a switching power supply (SMPS) - a mains voltage converter (AC / DC), which is combined with the MainBoard MSD3463-T4C1 board in this model. It is then necessary to measure its output voltages and, in their absence, the power switches (TO-220) and rectifier diodes of the converters should be checked for the probability of a short circuit.
In case of any breakdowns in the secondary circuits, the converter can operate in an emergency mode of a short circuit, and with a short circuit in the power elements of the primary circuit, the mains fuse or the current sensor at the source of the key is often cut off.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements, which can disable it in key mode, or provoke an excess of the maximum current or voltage values. These can be circuits supplying the PWM controller, damper or frequency setting circuits, or OOS (negative feedback) elements in the stabilization circuit. PWM controllers (PWM) LNK6777, in the absence of external damage and short circuit between the terminals, are checked by replacing them with known good ones.
- There is no picture, there is sound, it reacts to the remote control. Or the image may appear for a second when turned on and disappear immediately.
As a rule, in such cases there is no display backlight. Often the cause is a malfunction of the LEDs (open circuit, short circuit ...), or the connectors of the strips (strings), less often the LED driver turns out to be faulty.
It is impossible to check the LED bars for a break 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 tend to light one 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 an indicator of serviceability. In faulty LEDs, the zener diode will either be cut off, or pierced in the K / Z.
- The TV does not go into operation, does not respond to the remote control. The indicator on the front panel is constantly on or blinking.
Repair or diagnostics of the MSD3463-T4C1 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). In cases of attempts to repair the MB (SSB) board, it is necessary to check the serviceability of its elements - SPI Flash: MX25L6406E, Audio: TPA3110LD2 which may require replacement with new ones. If a BGA processor is installed, there is a possibility of a violation of the soldering of the contacts of its pins with the board (detected by warming up).
If there is no reception of television channels, but the TV is working properly from external devices, first of all, you need to check the supply voltage of the ST43WS-2A-E tuner and update the software. I2C communication pulses must be monitored with an oscilloscope.

General guidelines for limiting driver current after backlight repair.
To reduce the backlight current in LED drivers with the popular OB3350CP (OB3350) controller, the total resistance of the low-resistance measuring resistors from pin 5 (FB) to the case should be proportionally increased. The cathodes of LED strips (-LED) are connected to this point and the entire backlight current passes through the resistors, so the feedback voltage across these resistors is inversely proportional to the current in the LEDs.
Often a set of standard resistors connected in parallel in this circuit is enough, usually their values are within 1 - 3.9 Ohm, it is enough to remove one or two. For a more accurate current adjustment, you can change the ratings.


Users and owners of TVs should remember that attempts to repair the PHILIPS 39PHT4003 TV on their own without the appropriate qualifications and the necessary experience can lead to serious negative consequences!

 

DOWNLOAD SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------------------------------------------>     MSD3463-T4C1 Power supply & LED-Driver

 

 Additional MainBoard Repair
The appearance of the MainBoard MSD3463-T4C1 is shown in the figure below:



MSD3463-T4C1
The main features of the PHILIPS 39PHT4003 device:
Installed matrix (LED panel) K390WK9.
To power the backlight LEDs, a converter combined with the MSD3463-T4C1 main board is used, controlled by the OB3350CP PWM controller. The keys of the AOD4286 type are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using LNK6777 microcircuits and TO-220 power switches.
MainBoard - the main board (motherboard) is an MSD3463-T4C1 module, using SPI Flash chips: MX25L6406E, Audio: TPA3110LD2 and others.
The ST43WS-2A-E tuner provides reception of television programs and tuning to channels.

 

PHILIPS 39PHT4003 TV with LCD K390WK9, diagonal 39 "(99 cm) in 16: 9 format. The display technology of the model is implemented with LED backlighting.
The K390WK9 sensor and MainBoard MSD3463-T4C1 software provide high quality HD viewing at 1366x768 pixels in 720p (HD Ready). Supported media file formats: WMA, MPEG4, HEVC (H.265), MKV, JPEG.
The power of the acoustic system of sound 12 W (2x6 W) is provided by two speakers. Uses the NICAM stereo signal processing system and the Sound Surround function.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, VGA, HDMI x2, MHL, USB. A headphone output is provided. The digital tuner is capable of receiving TV channels in DVB-T, DVB-T2 standards.
The TV uses a power supply unit as part of the MainBoard.
Dimensions: with stand 888x560x202 mm, without stand 888x511x84 mm.
TV weight: with stand: 5.7 kg, without stand: 5.6 kg.
Attention! The K390WK9 panel of the PHILIPS 39PHT4003 LED TV is an expensive and unreliable element.
Avoid any impacts on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.

Instructions and updates
Documentation:
Quick start guide PDF file, 1.3 MB, published August 30, 2018
Brochure Version: 2.1.1, PDF file, 426.1 kB, published November 3, 2019
User manual PDF file, 8.2 MB, published August 30, 2018
Files can be downloaded from the manufacturer's website for model 39PHT4003 / 60.