Technical description and composition of the PHILIPS 40PFL3008H TV, type of panel and applicable modules. The composition of the modules.PHILIPS LED
Model: 40PFL3008H / 12
Chassis / Version: 17MB95S-1
Panel: VES400UNDS-03
LED driver (backlight): integrated into PSU
PWM LED driver: MP3394S
MOSFET LED driver: FQD7N10L, FQPF8N60C
Power Supply (PSU): 17IPS20P
PWM Power: FAN7529 (PFC), SG6742HR
MOSFET Power: FQPF9N50C (PFC), FQPF8N60
MainBoard: 17MB95S-1
IC MainBoard: MSD8WB9BXA-UTY, TC58NVG0S3HTA00, MX25L1606D, 24C02
Specifications 40PFL3008H
PHILIPS 40PFL3008H
General repair guidelines for TV LCD LED
Possible malfunctions
- The PHILIPS PFL3008H TV does not turn on, does not respond to the remote control and control panel buttons, indicators do not light up and do not blink.
Failure in such cases should begin to be looked for in the 17IPS20P power supply circuits. Then it is necessary to measure its output voltages and, in case of their complete or partial absence, it is necessary to check the operability of power switches (FQPF9N50C (PFC), FQPF8N60) and rectifier diodes of the converters for possible short circuit.
In case of diode breakdowns in the secondary circuits, the converter can operate in emergency short-circuit mode without output voltages, and during short circuit in the power elements of the primary circuit, the mains fuse and / or current sensor at the source of the key 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 (OOS) stabilization circuits. PWM controllers (PWM) FAN7529 (PFC), SG6742HR, if they do not have visible damage to the case and open fault between the terminals, are usually checked by replacement.
- There is no image, but there is sound and reaction to the remote control. Or for a second, the image may appear immediately after switching on.
In some of these cases, the malfunction is caused by a lack of backlighting on the display. 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.
It is impossible to check the LED line for breaks 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, as a rule, light up a single 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 a health indicator. In faulty LEDs, the zener diode will either be cut off or broken into short-circuit.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the 17MB95S-1 motherboard should begin by checking the stabilizers and power converters needed to power the microcircuits and matrix. If necessary, update or replace the software (software). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - MSD8WB9BXA-UTY, TC58NVG0S3HTA00, MX25L1606D, 24C02. Defective components should be replaced.
It should be remembered! Attempts to independently repair the PHILIPS PFL3008H 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!
Service manual and schematic diagram ------------> PHILIPS PFL3008H Chassis 17MB95S-1.
PSU -----------> 17IPS20P sсhematic diagram
To reduce the backlight current in LED drivers with the MP3394S (MP3394) controller, increase the resistance of the resistor from pin 6 (ISET) to the chassis. The maximum current in each channel (in milliamperes) for the Rset resistor (in kilo-ohms) is determined from the ratio 790 * 1.23V / (Rset + 0.4).
TV LED IC MP3394/MPS3394S LED Driver Diagnostics Throubleshooting
The earlier MP3394 was replaced by MPS3394S, which is an upgraded version of the same IC, and found in the 17IPS20 power supply board. It is the main heart of the backlighting LED drive and the failure of this IC can cause the TV not to start. This is a voltage step-up IC that takes 5-V to 28-V at its input pin 15 (Vin) and raises it to drive four independent strings of LEDs. It also performs other functions such as voltage regulation between the LED strings, and provides a dimming facility using pulse-width modulation (PWM). An important aspect of this IC is that it has built-in open and short LED protection circuitry. It is also able to sense the current and voltage of the LED matrix load and determine abnormal conditions. That means that if all the LEDs in the matrix go open or short, it will prevent the television from switching ON.
The IC has internal control logic that produces the GATE signal to drive an external MOSFET transistor. This is the transistor that is switched against an inductor to step-up the voltage, and the gate signal is produced only when the internal control logic detects normal conditions. It is able to determine normal/abnormal conditions through internal comparators, and one such is the LED Over-Voltage Protection (LED OVP) comparator that provides Short String Protection (SSP).
When the TV is switched ON, this IC is enabled through pin 2, by a voltage greater than 1.8-V. It first checks the circuit configuration, and then checks the over-voltage protection signal at (pin 12) to determine if the rectifier diode is open and whether the booster MOSFET (driven by the GATE signal) is short to ground. If the OVP voltage at pin 12 is lower than 70-mV (may be different for other board versions), then it disables itself and the TV will not start.
On the 17IPS20 board, the GATE signal is known as GATE_LED, which drives a bi-polar junction transistor (BJT) Q500 (BC858B). This transistor then drives Q502/Q503 MOSFET booster group of transistors to step-up the voltage (shown in the following pages of this article). In this circuit configuration the inductance coils are L500 and L501. The high voltage produced then goes into a group of rectifier diodes D503 and D504 producing a positive DC voltage for the LEDs. The over voltage protection signal is known as OVP_LED. Whilst all the LED strings take their power from this positive voltage source, they all have separate independent drain pins through the MPS3394S controller IC.
There are also other parameters to consider such as Under-Voltage Lock-Out (UVLO), which is determined by measuring the rising-edge of Vin. This parameter has to be between 3.5-V and 4.4-V, with 3.9-V being the typical value. It is a very clever IC as it can also detect open and short LED strings in the backlight array.
Although this diagnostic cannot tell you the condition of each individual diode, it can indicate the condition of each string of diodes in the backlight matrix. The MPS3394S IC (SOIC16 package) drives four separate strings of LEDs through dedicated open drain output pins. LED string 1 is driven by pin 11, LED string 2 by pin 10, LED string 3 by pin 9, and LED string 4 by pin 8. It also monitors the voltages at these pins so that if there was a shorted LED in one of the strings then it would disconnect that string. If the voltage at any of these pins is greater than 6.1-V, then this condition triggers the short circuit protection mechanism for disconnecting the string at that pin. It is also possible to determine an open string, and in this case, this condition is detected when the pin voltage is lower than 196-mV.
Interestingly, this IC is designed such that it will always try to light at least one string if it is working. The only time when the step-up converter shuts-down completely is if all the strings were either open, or short. Therefore, before you rush off to eBay to buy a new chip, measure the voltages at these pins to make sure that the diodes are not faulty. Otherwise, you will end up wasting a lot of time and money!
The appearance of the MainBoard 17MB95S-1 is shown in the figure below:17MB95S-1
17MB95S-1 can be used in TVs:
HYUNDAI DLH-32285 (Panel VES315WNDS-01), PHILIPS 40PFL3008H/12 (Panel VES400UNDS-03).
The appearance of the power supply
Main features of the PHILIPS 40PFL3008H device:
Installed matrix (LED-panel) VES400UNDS-03.
To power the backlight LEDs, a converter is used, combined with the power supply, controlled by the MP3394S PWM controller. As the power elements of the LED driver, keys of the type FQD7N10L, FQPF8N60C are used.
The necessary supply voltages for all nodes of the PHILIPS 40PFL3008H TV are generated by the 17IPS20P power module or its analogs using FAN7529 (PFC), SG6742HR microcircuits and power switches of the FQPF9N50C (PFC), FQPF8N60 type.
MainBoard - the main board (motherboard) is a 17MB95S-1 module, using microchips MSD8WB9BXA-UTY, TC58NVG0S3HTA00, MX25L1606D, 24C02 and others.