Technical description and composition of the PHILIPS 28PFL2908H TV, type of panel and applicable modules. The composition of the modules.PHILIPS LED
Model: 28PFL2908H / 12
Chassis / Version: VEM1.1ELA (17MB82S)
Panel: VES275WNVX-N01 // VES275WNVX-N02
LED backlight: 7020PKG PCT 40EA Rev0.2
LED driver (backlight): integrated into PSU
Power Supply (PSU): 17IPS61-3P
PWM Power: ICE3BR0665J
MainBoard: 17MB82S
IC MainBoard: CPU: MT8520LUNU, DEMODULATOR: MT5135AE, SPI FLASH: 25Q16, EEPROM: 25Q64, AUDIO: AD82587D, DRAM: K4B1G1646G-BCK0
Tuner: NoName
Specifications 28PFL2908H
PHILIPS 28PFL2908H
General repair guidelines for TV LCD LED
Possible malfunctions
- The PHILIPS 28PFL2908H TV does not turn on, does not respond to the remote control and the control panel buttons, does not light up or blink indicators.
Most likely in this case, the main switching power supply (IPS) 17IPS61-3P is faulty. In the absence of the necessary supply voltages in the secondary circuits of the converters, it is necessary to check the power switches and rectifier diodes for a possible partial or complete breakdown.
In case of breakdowns in the secondary circuits, the converter, as a rule, can emergency work in the short circuit mode, and during short circuit in the power elements of the primary circuit, the mains fuse usually breaks.
Breakdown of power switches (MosFet) in pulsed sources is sometimes caused by malfunctions of other circuit elements, for example, in circuits supplying a PWM controller, frequency-setting or damper ones, as well as in negative feedback circuits (OOS) of stabilization. PWM controllers (PWM) ICE3BR0665J, if they do not have visible damage to the case and open short circuit between the terminals, are usually checked by replacement.
- There is no image, there is sound, it reacts to the remote control, channels are switched. In some cases, the image appears when you turn on and immediately disappears.
A malfunction is usually most likely in these cases at the backlight nodes of the display matrix. 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.
To check the LED strips to open all the transitions of the LEDs, several tens of volts or more are needed, it is best to use a current source for such purposes. The breakage of several PN junctions connected in series cannot be detected with a multimeter or tester. In such cases, it is necessary to open the panel and check each LED. If your multimeter cannot open the LED transitions in forward bias, you can sometimes detect the presence of a PN junction of the protective zener diode by connecting the probes in the opposite direction. If the zener diode is broken or broken in short-circuit, then the LED is faulty and needs to be replaced.
- 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 17MB82S 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). Board repair and replacement of CPU chips: MT8520LUNU, DEMODULATOR: MT5135AE, SPI FLASH: 25Q16, EEPROM: 25Q64, AUDIO: AD82587D, DRAM: K4B1G1646G-BCK0 are made with the necessary equipment, and the corresponding element base. Faults associated with the application of BGA processor soldering technologies can be localized by the heating method.
Before replacing the NoName tuner, if there is no tuning to the channels, you must first check the software and the supply voltage at its terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus
Attention TV owners! Attempts at self-repair of PHILIPS 28PFL2908H are not recommended by the manufacturer and can lead to serious negative consequences!
Service manual and schematic diagram ----------------> PHILIPS 28PFL2908H Chassis VEM1.1ELA (17MB82S).
FIRMWARE FOR SPI FLASH, EEPROM ------------> PHILIPS 28PFL2908H/12 VEM1.1ELA, Main: 17MB82S, Panel: VES275WNVX-N01
The appearance of the MainBoard 17MB82S is shown in the figure below:17MB82S
The appearance of the power supply
Main features of the PHILIPS 28PFL2908H device:
Installed matrix (LED-panel) VES275WNVX-N01 or VES275WNVX-N02.
To power the backlight LEDs, a converter is used, combined with a power supply.
The necessary supply voltages for all nodes of the PHILIPS 28PFL2908H TV are generated by the 17IPS61-3P power supply module or its analogs using ICE3BR0665J microcircuits.
MainBoard - the main board (motherboard) is a 17MB82S module using CPU chips: MT8520LUNU, DEMODULATOR: MT5135AE, SPI FLASH: 25Q16, EEPROM: 25Q64, AUDIO: AD82587D, DRAM: K4B1G1646G-BCK0 and others.
The NoName tuner provides television reception and channel tuning.
