Technical description and composition of the PHILIPS 42PFL74X6 TV, type of panel and applicable modules. The composition of the modules.PHILIPS LED
Model: 42PFL74X6
Chassis / Version: Q552.2E LA
Panel: TFT-LCD LC420EUF-SDA1 (LGPH) B
LED driver (backlight): with integrated PSU
PWM LED driver: DDA009
Power Supply (PSU): DPS-139AP A B 2722 171 90338
PWM Power: NCP1608B (PFC), S101, DDA010, 2QS02G
MainBoard: 313926868651 TV550 2K11 EU7
IC MainBoard: PNX85537, ST1S10PH ST1S10B (8), TPA3123D2, TPS53126PW
Tuner: TH2603
Specifications 42PFL7486H
PHILIPS 42PFL74X6
General repair guidelines for TV LCD LED
In the case when the 42PFL74X6 does not turn on, does not respond to the remote control and the front panel buttons, does not blink bulbs and does not show any signs of operability, the power supply module DPS-139AP AB 2722 171 90338 is probably faulty in this case. First of all, it is necessary to replace the swollen filter capacitors rectifiers, if any. If the mains fuse is broken in the power supply, in most cases a breakdown of the power key (s) is detected, which can be integrated with the PWM controller, or a separate field-effect transistor can be used. The rectifier bridge diodes and the electrolytic capacitor of the mains rectifier filter should also be checked.
Power switches in pulsed power supplies (SMPS) fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The reason may be a malfunction of the PWM controller chip NCP1608B, S101, DDA010, 2QS02G, which can only be checked by replacing with a new or obviously working one.
If the PHILIPS 42PFL74X6 TV does not have an image, but there is sound, there may be a malfunction in the backlight circuits of the TFT-LCD LC420EUF-SDA1 (LGPH) B LED panel.
Often in the absence of backlighting, disassembling the panel is required. It is necessary to check the serviceability of the transitions of the LEDs, as well as the reliability of the contact connections in the lines and connectors.
It is impossible to detect a break in the LED line without disassembling the panel with a simple multimeter. LEDs are connected in series and to open their transitions, a voltage of several tens of volts is required. Ideally, a current source is suitable for such purposes. You can open the panel and check each LED separately. Typically, Chinese multimeters light up a single 3-volt LED, if you connect the probes in the forward direction to it (red probe to the anode, black to the cathode). In dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of health. In the event of a LED malfunction, its zener diode will either be cut off or broken into short-circuit.
Diagnosis and repair of the motherboard 313926868651 TV550 2K11 EU7 usually begins with a test of the performance of the stabilizers and power converters of the module chips. In some cases, a software update is required.
When repairing an MB board, you need to check its components PNX85537, ST1S10PH ST1S10B (8), TPA3123D2, TPS53126PW. Defective items should be replaced. If BGA chips are installed, their malfunction is usually localized by heating.
Before changing the tuner TH2603, if it is not possible to tune to television channels, you should make sure that there are supply voltages that must be measured at the corresponding terminals of the tuner and check the software for correctness. The pulses of the data exchange of the tuner with the processor can be controlled by an oscilloscope
It should be remembered! Attempts to repair the PHILIPS 42PFL74X6 TV, in the absence of the necessary qualifications and experience, are categorically not recommended and are fraught with negative consequences, up to the complete non-repairability of the device!
The appearance of MainBoard 313926868651 is shown in the figure below:313926868651
313926868651 can be used in TVs:
PHILIPS 37PFL6606H / 60 (Panel LC370EUF-SDA1 (LGPH) B p / n: 932228180682), PHILIPS 42PFL74X6 (Panel TFT-LCD LC420EUF-SDA1 (LGPH) B).
The appearance of the power supply
Main features of the PHILIPS 42PFL74X6 device:
Installed matrix (LED-panel) TFT-LCD LC420EUF-SDA1 (LGPH) B.
To power the backlight LEDs, a converter is used, combined with a power supply unit, controlled by the DDA009 PWM controller.
The necessary supply voltages for all nodes of the PHILIPS 42PFL74X6 television are generated by the DPS-139AP power module or its analogs using NCP1608B (PFC), S101, DDA010, 2QS02G microcircuits.
MainBoard - the main board (motherboard) is a module 313926868651, using chips PNX85537, ST1S10PH ST1S10B (8), TPA3123D2, TPS53126PW and others.
The TH2603 tuner provides TV reception and channel tuning.