Technical description and composition of the PHILIPS 20PF8846 TV, panel type and applicable modules. The composition of the modules.PHILIPS
Model: 20PF8846
Chassis / Version: LC4.1E AA
Panel: 20 inch
Inverter (backlight): BL6L70P3 LIPS 3122 137 23101 TCI-D2S (-d)
PWM Inverter: UBA2070T (16H) PL
Power Supply (PSU): BL6L70P3 LIPS 3122 137 23101 TCI-D2S
PWM Power: L6562D (PFC), TEA1533AT (14)
MOSFET Power: S15L60, P4NK80ZFP, 10NK60ZFP
MainBoard: 3139-123-58333 3139 123 58333 WK424.1
IC MainBoard: CPU: TDA15021H; Scaler: GM5221
Tuner: UR1316S / A
Specifications 20PF8846
PHILIPS 20PF8846
General recommendations for repairing TV LCD
It is recommended to start the diagnostics of a malfunction of the PHILIPS 20PF8846 TV, as well as all other electronic devices, with an external examination of both external and internal elements and modules. It often happens that some damage to elements or connections helps determine the direction of the troubleshooting. Carbonized paint on the upper layer of resistors, electrolytic capacitors of rectifier filters swollen after boiling, cracked soldering at the terminals of heating elements or transformers can often suggest the cause of the defect and possible consequences.
If PHILIPS 20PF8846 does not turn on, no control lights on the front panel light up or blink, therefore, there is a very high probability of a malfunction of the BL6L70P3 LIPS 3122 137 23101 TCI-D2S power supply module. When diagnosing and repairing the power supply, after replacing the swollen capacitors of the secondary rectifier filters (if any), you must first check the mains fuse. If it is broken, check the power switch S15L60. P4NK80ZFP. Pp10NK60ZFP and rectifier bridge diodes for avalanche (thermal) breakdown.
If a breakdown of the power switch of the flyback converter of the power supply unit is detected, it should be remembered that it does not fail by itself without any reasons that should be sought by checking other elements of the primary circuit - electrolytic capacitors, PWM controller L6562D (8) pl. . TEA1533AT (14), UBA2070T (16), which can only be checked by replacement, as well as other semiconductor elements (diodes, transistors, zener diodes).
It is somewhat more difficult to find faults in the converter of the power module with an active KKM (power factor corrector).
If the PHILIPS 20PF8846 does not have an image, but there is sound and the TV is controlled by the remote control, a malfunction in the display backlight nodes is likely. The lamps or the power converter - inverter may be faulty. Often in such cases, when you turn on the TV, an image appears and immediately disappears. First of all, it is necessary to verify the operability of the electrolytic capacitors of the rectifier filter supplying the inverter, and check the LCD lamps by connecting external and obviously serviceable for diagnosis to the connectors.
Repairing the BL6L70P3 LIPS 3122 inverter 137 23101 TCI-D2S (-d) is difficult because in case of any malfunction or abnormal situation, even if the lamps are unevenly worn, a protection is triggered that turns it off for fire safety purposes. Diagnostics become impossible and protection needs to be disabled.
In such cases, special care should be taken during diagnostics, and after completion of all repair work, it is necessary to restore the circuit and the inverter protection for further safe operation of the TV.
Remember! Attempts to self-repair by users of the PHILIPS 20PF8846 TV without the appropriate qualifications and the necessary experience can lead to serious negative consequences!
Service manual and schematic diagram 20PF8846 Chassis LC4.1E AA
MODELS: 14PF7846, 15PF8946, 17PF8946, 20PF8846, 20PF7846, 23PF8946
The appearance of MainBoard 3139-123-58333 is shown in the figure below:3139-123-58333
3139-123-58333 can be used in TVs:
PHILIPS 20PF8846 (Panel 20 inch), PHILIPS 23PF8946 / 58 (Panel QD23WL05).
PSU Advanced
According to the conditions of compliance with modern world standards for household switching power supplies, the BL6L70P3 module provides for the use of a Power Factor Correction unit. The PFC circuit is a flyback converter based on the L6562D PWM controller. The reactance of an electrolytic capacitor of a line filter at a frequency of 50-60 Hz is usually not more than 20-30 ohms and its charge directly from the network through open diodes could reach tens of amperes per pulse if no filtering were applied.
As a result of the PFC conversion, an increased voltage on the capacitor (about 380V) cannot directly open the rectifier diodes, on the anode of which the voltage will always be slightly less (about 300V) and then its charging current will always be limited by the elements of the PWM controller. As a result, the envelope of the high-frequency pulses of the consumed current will repeat the shape and phase of the input sinusoidal voltage. The presence of an increased voltage (+ 380V) on the network capacitor indicates the serviceability of the PFC node.
The appearance of the power supply
Main features of the PHILIPS 20PF8846 device:
Installed matrix (LCD-panel) 20 inch.
To power the backlight, an inverter BL6L70P3 is used, it is controlled by a PWM controller UBA2070T (16n), pl.
The necessary supply voltages for all nodes of the PHILIPS 20PF8846 TV are generated by the BL6L70P3 power module or its analogs using L6562D (PFC), TEA1533AT (14) microchips and power switches of the S15L60, P4NK80ZFP, 10NK60ZFP type.
MainBoard - the main board (motherboard) is a module 3139-123-58333, using CPU chips: TDA15021H; Scaler: GM5221 and others.
The tuner UR1316S / A provides TV reception and channel tuning.
