Technical description and composition of the GOLDSTAR LT-40T440F TV, panel type and modules used. The composition of the modules.GOLDSTAR LED
Model: LT-40T440F
Chassis / Version: MT31SR
Panel: LVF400NEAL
LED backlight: 67-H99985-0A0 40S4600
LED driver (backlight): integrated into PSU
PWM LED driver: MAP3204T
MOSFET LED driver: 20N15GH
Power Supply (PSU): 40-EL3910-PWF1XG 81-EL391C0-PL290AA
PWM Power: FAN6754MR
MOSFET Power: MDF10N65B
MainBoard: MT31SR 40-MT31SR-MAD2HG
IC MainBoard: CPU: MT5531NDNT 1414-BCAH, SPI Flash: 25Q64FVSIG, Audio: TAS5707, AZ1084S2-3.3, DRV632
Tuner: RE221ZN
LT-40T440F Specifications
GOLDSTAR LT-40T440F
General recommendations for TV LCD LED repair
Possible manifestations of defects
- GOLDSTAR LT-40T440F does not turn on and does not show any signs of operability at all. Does not blink indicators and does not respond to control buttons.
In such cases, the fault should be looked for primarily in the 40-EL3910-PWF1XG power module. It is then necessary to measure its output voltages and, if they are absent, the power switches (MDF10N65B) and rectifier diodes of the converters should be checked for the probability of a short circuit.
In case of breakdowns in the secondary circuits of the converter, it can usually work in an emergency mode in a short circuit mode, and with a short circuit in the power elements of the primary circuit, the mains fuse or current sensor in the source of the key is most often cut off.
Breakdown of power switches (MosFet) in switching sources is sometimes caused by malfunctions of other circuit elements, for example, in the circuits supplying the PWM controller, frequency setting or damper, as well as in the circuits of Negative Feedback (OOS) stabilization. PWM controllers (PWM) FAN6754MR, if they have no visible damage to the case and an outright short circuit between the pins, are usually checked by replacing.
- There is no picture, but there is sound, it reacts to the remote control. Or the image appears when turned on and disappears immediately
The malfunction in most of such cases is found in the nodes and elements of the LED panel backlight. The reason may be in the breakage of the LEDs, in the stabilization of their power supply, or in the violation of the contact connections of the strings connectors,
Without a special current source, it is impossible to check the line of series-connected LEDs, and it is unsafe for them to use any voltage sources over 12V for this purpose. Then all that remains is to open the panel and check each LED separately. Usually, Chinese multimeters with 9V power supply lightly light one 3-volt LED, if you connect the probes to it in the forward direction, the red probe to the anode, the black one to the cathode. For dual 6-volt LEDs, the PN junction of its emergency zener diode can serve as an indicator of the LED health. In the event of a malfunction of the LED, its zener diode will either be cut off or pierced in the K / Z.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the MT31SR motherboard should begin with checking the stabilizers and power converters necessary to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Often the MB (SSB) board must be replaced in case of complex malfunctions that are difficult to detect. When trying to repair, you should check its elements - CPU: MT5531NDNT 1414-BCAH, SPI Flash: 25Q64FVSIG, Audio: TAS5707, AZ1084S2-3.3, DRV632 and replace the failed chips with new ones. Some malfunctions may be associated with the use of BGA soldering technologies in modern Main Board. Usually such defects are detected by local heating of the chip.
If there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as that the supply voltages on the terminals of the RE221ZN tuner match. It is also necessary to check with an oscilloscope the presence of pulses of data exchange between the tuner and the processor via the I2C bus.
Attention to TV owners! Attempts to repair the GOLDSTAR LT-40T440F on your own are not recommended by the manufacturer and can lead to serious negative consequences!
DOWNLOAD FIRMWARE FOR SPI FLASH -----------> GOLDSTAR LT-40T440F, Main: MT31SR 40-MT31SR-MAD2HG, Panel: LVF400NEAL
The appearance of the MainBoard MT31SR is shown in the figure below:MT31SR
External view of the power supply
Main features of the GOLDSTAR LT-40T440F device:
Installed matrix (LED-panel) LVF400NEAL.
A converter combined with a power supply is used to power the backlight LEDs, and is controlled by the MAP3204T PWM controller. The keys of the 20N15GH type are used as power elements of the LED driver.
The formation of the necessary supply voltages for all nodes of the GOLDSTAR LT-40T440F TV is carried out by the 40-EL3910-PWF1XG power module, or its analogs using FAN6754MR microcircuits and MDF10N65B power switches.
MainBoard - the main board (motherboard) is an MT31SR module, using CPU chips: MT5531NDNT 1414-BCAH, SPI Flash: 25Q64FVSIG, Audio: TAS5707, AZ1084S2-3.3, DRV632 and others.
Tuner RE221ZN provides reception of television programs and tuning to channels.
TV GOLDSTAR LT-40T440F with LCD LVF400NEAL, diagonal size 40 "(102 cm) 16: 9. The required screen brightness of 320 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 2000: 1. Dynamic contrast ratio of 100000: 1 is achieved by special control of the LEDs. The LED panel of this TV is equipped with edge LED backlighting. 1080p (Full HD). Input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal shaping occurs in standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats : MP3, WMA, MPEG4, MKV, JPEG.
Speaker power 16 W (2x8 W) is provided by two speakers. The NICAM STEREO audio processing system is used.
External interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, component, VGA, HDMI x2, USB x2. A headphone output is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector on the TV case is used, this interface supports resolutions: 640x480, 800x600, 1024x768, 1280x1024, 1360x768, 1920x1080.
The digital tuner is capable of receiving television channels in the DVB-T, DVB-C, DVB-T2 standards.
Overall dimensions: 930x590x180 mm.
Attention! Panel LVF400NEAL LED-TV GOLDSTAR LT-40T440F is an expensive and unreliable element.
Do not allow any impact on the glass and pressure on the screen surface to avoid damage to the LED panel!
It is also unsafe for liquid to spill onto the screen. Sometimes one drop is enough if it drips down the glass onto the cables to make the TV unrepairable.