Technical description and composition of the TOSHIBA 40L5435 TV, type of panel and applicable modules. The composition of the modules.TOSHIBA LED
Model: 40L5435 40L5435DG
Chassis / Version: 17MB95M
Panel: VES400UNVS-3D-N01
T-CON: 13VNB_FP_SQ60MB4C4LV0.0
LED driver (backlight): integrated into PSU
PWM LED driver: MP3394
MOSFET LED driver: FQD7N10L
Power Supply (PSU): 17IPS71
PWM Power: FAN6300
MOSFET Power: FQPF8N60C
MainBoard: 17MB95M
IC MainBoard: MT5820LUNU, 25L1605, H27U2G8F2CTR-BC, H5TQ2G63DFR
Tuner: Tuner
Specifications 40L5435
TOSHIBA 40L5435
General repair guidelines for TV LCD LED
Possible manifestations of defects
- The TOSHIBA 40L5435 does not turn on. There are no signs of operability. The indicators on the front panel do not light or flash, the TV does not respond to the remote control and control buttons.
Most often, with such manifestations, the 17IPS71 main power module is found to be faulty. It is then necessary to measure its output voltages and, if they are absent, you should check the power switches (FQPF8N60C) and the rectifier diodes of the converters for a short circuit probability.
In case of breakdowns of semiconductors in the secondary circuits of any converter, as a rule, it can operate in emergency short circuit mode without output voltages, and during short circuit in the elements of the primary circuit, the mains fuse and, less often, the current sensor at the source of the key are most often cut off.
The breakdown of Mos-Fet keys used in pulsed sources is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency-setting or damping circuits, as well as in Negative Stabilization Feedback. PWM chips of the FAN6300 are usually checked by replacing them with new ones, or those that are obviously working.
- There is no image, but there is sound, it reacts to the remote control. Or the image appears when you turn it on and immediately disappears
In some of these cases, the malfunction is caused by a lack of backlighting on the display. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
When trying to detect a break in the LED lines, it should be taken into account that it is difficult to do this without disassembling the panel. For example, a current source is needed to open PN junctions connected in series.
- The indicator blinks or lights constantly, the TV does not turn on, does not respond to the remote control.
Repair or diagnostics of the 17MB95M 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). If it is not possible to replace the MB board (SSB), you need to check the health of its elements - MT5820LUNU, 25L1605, H27U2G8F2CTR-BC, H5TQ2G63DFR. Defective components should be replaced.
Before replacing the 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
We recommend the owners of the 40L5435 TV for repair only to qualified specialists with the necessary work experience! Self-repair attempts without the appropriate knowledge and skills can lead to irreversible negative consequences!
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).
SCHEMATIC DIAGRAM / SERVICE MANUAL ------------------> 17IPS71-R3 Power supply
Repair MainBoard
The appearance of the MainBoard 17MB95M is shown in the figure below:
17MB95M
17MB95M can be used in TVs:
TOSHIBA 40L5455R (Panel VES400UNVS-3D-N01), TOSHIBA 40L5435 40L5435DG (Panel VES400UNVS-3D-N01).
The appearance of the power supply
Main features of the TOSHIBA 40L5435 device:
Installed matrix (LED-panel) VES400UNVS-3D-N01.
The matrix control uses the Timing Controller (T-CON) 13VNB_FP_SQ60MB4C4LV0.0.
To power the backlight LEDs, a converter is used, combined with a power supply, controlled by the MP3394 PWM controller. As power elements of the LED driver, keys of the FQD7N10L type are used.
The necessary supply voltages for all nodes of the TOSHIBA 40L5435 TV are generated by the 17IPS71 power module or its analogs using FAN6300 microcircuits and power switches of the FQPF8N60C type.
MainBoard - the main board (motherboard) is a 17MB95M module, using chips MT5820LUNU, 25L1605, H27U2G8F2CTR-BC, H5TQ2G63DFR and others.
The Tuner provides TV reception and channel tuning.
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!
Brand: TOSHIBA, Model: 40L5435.
Short from TV: LCD, LED backlight, 40 ", 1920x1080, 1080p Full HD, 3D, DVR, sound: 16W, HDMI: 3, Internet access, Wi-Fi, Smart TV.
The composition uses MainBoard 17MB95M and an LCD panel (matrix) VES400UNVS-3D-N01.
Power Supply Unit (PSU) 17IPS71 Power Supply.
TOSHIBA 40L5435 LED TV with VES400UNVS-3D-N01 LCD, 40 "(102 cm) diagonal, 16: 9 format. The required screen brightness of 300 cd / m² is provided by LED backlighting. The ratio of maximum brightness to minimum (contrast) is 4000: 1. This model uses side lighting from Edge LEDs.
There is support for 3D images with active (shutter) technology for separating the right and left channels. The design and technical capabilities of the TV include watching programs and movies in high quality HD at a resolution of 1920x1080 pixels in a graphical decomposition according to the standard 1080p (Full HD).
The 40L5435 is equipped with SMART software, integrated applications and the ability to work on the Internet. Connecting to the Internet can be done via Wi-Fi. The input high-frequency or video signal can be processed in analogue systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, WMA, MPEG4, Xvid, DivX, MKV, JPEG.
The power of the sound system 16 W (2x8 W) provide two speakers. It uses a NICAM stereo signal processing system and Sound Surround.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, SCART, RGB, VGA, HDMI x3, USB x2, Ethernet (RJ-45), Wi-Fi. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080.
A digital tuner is capable of receiving television channels in the DVB-T MPEG4, DVB-C standards.
The power consumed by the TV in the operating mode from the network is 75 watts.
Overall dimensions: with stand 925x498x215 mm, without stand 925x453x89 mm.
TV Weight: with stand: 9.5 kg, without stand: 5.85 kg.
Attention! The VES400UNVS-3D-N01 panel of the TOSHIBA 40L5435 LED TV is an expensive and unreliable element.
Avoid any impact on the glass and pressure on the surface of the screen to avoid damage to the LED panel!
It is also unsafe to get liquid on the screen. Sometimes one drop is enough if it flows down the glass onto the cables so that the TV becomes unrepairable.