Technical description and composition of the PHILIPS 42PFL7864 TV, type of panel and applicable modules. The composition of the modules.
PHILIPS
Model: 42PFL7864
Chassis / Version: Q548.1E LA
Panel: 42 inch
Inverter (backlight): integrated into PSU
PWM Inverter: DDA003A (24pin), DDA002B
Power Supply (PSU): DPS-298CP
PWM Power: DDA002B (PWM 20 pin), 1606B (PFC), 3BS3LJ (PWM 8pin)
MainBoard: 3139_123_64423V2 PNL 3139 123 64423v2 BD 3139 123 64433v2
IC MainBoard: PNX8539EH24182 LAN9420-NU TDA9996HL / C4
Tuner: HD1816AF / BHXP.
Specifications 42PFL7864H
PHILIPS 42PFL7864
General recommendations for repairing TV LCD
It is advisable to start repairing all electronic devices, including the PHILIPS TV, based on the Q548.1E LA chassis, with an external examination of its external and internal elements. Often, by the external signs and nature of the damage to the elements, it becomes possible to draw some conclusions and determine a further algorithm for finding a defect before making the necessary measurements at control points. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
If PHILIPS 42PFL7864 does not turn on, no control lights on the front panel will light or blink, therefore, there is a very high probability of a DPS-298CP power supply module malfunctioning. In some cases, only the processor power regulator may be faulty. When diagnosing and repairing the power supply, first of all, replace the swollen capacitors of the filter of the secondary rectifiers and check the fuse and, if it is broken, it is necessary to identify the cause. Often in such cases, an avalanche (thermal) breakdown is detected in the power semiconductor elements of the module — rectifier diodes and transistors in the primary circuit.
It should be remembered that in the practice of repair, usually the power switches in switching power supplies (SMPS) do not fail due to their poor quality and, in such cases, it is necessary to look for the cause that led to a malfunction and provoked a breakdown of the key. Most often, the culprits of the accident are dried electrolytic capacitors or dangling resistors in the primary circuit, or the PWM controller chip itself may be faulty. It is also necessary to check all the semiconductor elements of the stabilization circuit in the primary and secondary circuit.
If PHILIPS 42PFL7864 does not have an image, but there is sound, there is a possibility of a malfunction of the backlight or power converter. You should also make sure that the electrolytic capacitors of the secondary rectifiers of the common power supply are working. When disabling the inverter protection (to enable diagnostics), special care must be taken in view of the risk of failure of the power elements. After completing all repair work, it is imperative to restore the protection circuits for full and safe further operation of the TV by the user.
In cases of attempts to repair the motherboard EH009.3 S PL5.A, HD1816AF / BHXP., It is necessary to check the performance of the stabilizers or power converters of its microcircuits and, if possible, update the software (software). BGA chips can in most cases be diagnosed by local heating.
Owners and users of the PHILIPS 42PFL7864 TV must remember that self-repair without special knowledge, skills and qualifications can be fraught with negative consequences, which can lead to complete non-repairability of the device!
Service manual and schematic diagram 42PFL7864 Chassis Q548.1E LA
PSU -----------------> DPS-298CP-2 DELTA schematic diagram
The appearance of MainBoard 3139_123_64423V2 is shown in the figure below:3139_123_64423V2
3139_123_64423V2 can be used in TVs:
PHILIPS 32PFL7864H/60 (Panel LC320WUF-SBN1), PHILIPS 32PFL8404H/60 (Panel LC320WUF (SB)(N1) code 181 p/n: 932226687682), PHILIPS 37PFL8404H/60 (Panel T370HW03 V.2 code 189), PHILIPS 42PFL7674H/60 (Panel LC420WUF(SB)(N1)), PHILIPS 42PFL7864 (Panel 42 ), PHILIPS 42PFL8404H/60 (Panel LC420WUF-SBN1 code 183 p/n: 932226646682).
PSU Advanced
The DPS-298CP power supply module is made using the Power Factor Correction (PFC) scheme to eliminate multiple AC harmonics introduced into the power supply by the device. The PFC assembly is a Step-Up Converter based on a 1606B PWM controller that evenly distributes high-frequency impulses of the charging current of the electrolytic capacitor of the rectifier filter of the mains voltage evenly over a period of 50 Hz. The current of its charge in this case will already be determined not by its reactance (usually 10-30 ohms for the network frequency), but by the elements of the converter. As a result, a change in the amplitude of the pulses (envelope) of the consumed current of the converter will repeat the shape and phase of the input sinusoidal voltage. The availability of an increased voltage (about + 380V) in the operating mode on the capacitor of the line filter indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the PHILIPS 42PFL7864 device:
Installed matrix (LCD-panel) 42 inches.
To power the backlight, a converter is used, combined with a power supply, controlled by a PWM controller DDA003A (24pin), DDA002B.
The necessary supply voltages for all nodes of the PHILIPS 42PFL7864 television are generated by the DPS-298CP power supply module or its analogs using DDA002B (PWM 20 pin), 1606B (PFC), 3BS3LJ (PWM 8pin) microcircuits.
MainBoard - the main board (motherboard) is a 3139_123_64423V2 module, using PNX8539EH24182 LAN9420-NU TDA9996HL / C4 chips and others.
Tuner HD1816AF / BHXP. provides TV reception and channel tuning.
