Technical description and composition of the HAIER LE39B8550T TV, panel type and modules used. The composition of the modules.
HAIER LED
Model: LE39B8550T
Chassis / Version: MS34637-ZC01-01
Panel: LC390TA2A
LED backlight: LED39D07-ZC15AG-02 30339007031
LED driver (backlight): integrated into MainBoard
PWM LED driver: SO-8
MOSFET LED driver: TO-252
Power Supply (PSU): integrated into MainBoard
PWM Power: PWM SOT23-6
MOSFET Power: 70RJ8 TO-252
MainBoard: MS34637-ZC01-01
IC MainBoard: CPU: MSD3463GSA-SW, SPI Flash: GD25Q64, AUDIO, DC / DC
Tuner: NoName
Specifications LE39B8550T
HAIER LE39B8550T
General recommendations for TV LCD LED repair
Possible malfunctions
- HAIER LE39B8550T 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 main power supply, the AC / DC converter of the mains voltage, which is combined with the MainBoard MS34637-ZC01-01, may be faulty. It is necessary to measure its output supply voltages, and in their absence, check the serviceability of the power switches (70RJ8 TO-252) of the converters and rectifier diodes for the probability of breakdown in semiconductor PN junctions.
In case of breakdowns in the secondary circuits, the converter can operate in short-circuit mode, and in case of short-circuit in the elements of the primary circuit, the mains fuse usually breaks off.
Breakdown of Mos-Fet keys used in switching power supplies is often caused by malfunctions of other elements, for example, in the power supply circuit of a PWM controller, in frequency setting or damper circuits, as well as in negative feedback stabilization. PWM microcircuits (PWM) PWM SOT23-6 are usually checked by replacing them with new ones, or known to be working properly.
- There is no image, the screen is black, there is sound, sometimes you can see barely noticeable outlines of the image in the ambient light of the screen.
The malfunction in most of these cases is found in the nodes and elements of the LED panel backlight. Most often the reason for this is a break in the LEDs, or poor contact in the connectors of the brackets, less often the LED driver may be faulty.
It should be remembered that it is not possible to determine an open circuit in the LED lines without disassembling the panels using a tester or multimeter without an additional device, for example, a current source. To open all PN junctions connected in series at once, a voltage of several tens of volts may be required. Then you need to open the panel and check each LED separately with a multimeter. If the capabilities of your multimeter do not allow opening the LED in the forward direction or dual LEds are used, then the PN transition of the emergency zener diode can indirectly serve as an indicator of serviceability. In the event of a malfunction of the LED-a, the PN junction of the Zener diode will either be cut off, or broken through in the K / Z.
If the HAIER LE39B8550T has no picture, but there is sound, often the LC390A2A display backlight simply does not work. Moreover, in LED TVs, the LEDs inside the panel usually fail, less often the LED driver.
In such cases, you can see a barely noticeable image with a successful hit of external light on the screen.
Replacing the LEDs requires disassembling the LC390A2A LCD panel, a process that requires experience and qualifications from the technician. We do not recommend doing such work on your own to TV owners and craftsmen who do not have experience in repairing LCD panels
If there is no image, and the backlight is on, the screen becomes slightly lighter when turned on, and in an open TV you can see light through the holes in the panel case.
In this case, the panel may also be faulty - damage to strips, loops, for example, as a result of moisture ingress after unsuccessful washing of the screen, the T-CON (Timing Controller) board may be faulty. But the main board MainBoard MS34637-ZC01-01 often turns out to be faulty, a software failure is also possible.
Then, first of all, you need to check the panel supply voltage, the fuses on the T-CON board, as well as the supply and reference voltages of the column and line drivers - VGH, VGL, Vcom.
If these measurements are within normal limits, it is necessary to trace the passage of LVDS signals from the MainBoard MS34637-ZC01-01 with an oscilloscope, as well as synchronizing signals to the loops with drivers.
Flooded or unsuccessfully washed screens of LED TVs can be restored, in about half of the cases, usually if significant damage has not formed in the loops and panel strips.
READ HOW TO REPAIR THE TV LED BACKLIGHT --------------> HERE.
- The TV does not turn on, the indicator signals the standby or operating mode, or blinks.
Repair or diagnostics of the MS34637-ZC01-01 motherboard should begin with checking the stabilizers and power converters required to power the microcircuits and matrix. If necessary, you should update or replace the software (software). Complicated repair of MB (SSB) board is in some cases possible and practiced by repairmen. To do this, check and, if necessary, replace the elements of the CPU, SPI Flash, AUDIO, DC / DC. Malfunctions in BGA chips are usually easy to detect by warm-up.
In cases where there is no tuning for terrestrial or cable TV channels, you should make sure that the software is correct, as well as in accordance with the nominal supply voltages at the NoName tuner terminals. 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 HAIER LE39B8550T by yourself are not recommended by the manufacturer and can lead to serious negative consequences!
Additional MainBoard Repair
The appearance of the MainBoard MS34637-ZC01-01 is shown in the figure below:
MS34637-ZC01-01
The main features of the HAIER LE39B8550T device:
Installed matrix (LED panel) LC390TA2A.
To power the backlight LEDs, a converter combined with the MS34637-ZC01-01 main board is used, controlled by the SO-8 PWM controller. TO-252 switches are used as power elements of the LED driver.
The power module is combined with the MainBoard and is made according to the AC / DC flyback voltage converter using SOT23-6 PWM microcircuits and 70RJ8 TO-252 power switches.
MainBoard - the main board (motherboard) is a MS34637-ZC01-01 module using CPU chips: MSD3463GSA-SW, SPI Flash: GD25Q64, AUDIO, DC / DC and others.
Tuner NoName provides reception of television programs and tuning to channels.
TV HAIER LE39B8550T with LCD LC390A2A, diagonal 39 "(99 cm) in 16: 9 format. The required screen brightness of 220 cd / m² is provided by LED backlighting. Contrast, as the ratio of maximum brightness to minimum, is 3000: 1. The LED panel of this TV is equipped with edge LED backlighting.
The LC390A2A sensor and MainBoard MS34637-ZC01-01 software realize HD image quality at a resolution of 1366x768 pixels in 720p (HD Ready). Supported media file formats: MP3, WMA, 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, VGA, HDMI x2, USB. A headphone output is provided. The digital tuner is capable of receiving television channels in the DVB-T, DVB-T2, DVB-C standards.
The power supply is used as part of the MainBoard.
Dimensions: with stand 885x558x200 mm, without stand 885x507x71 mm.
TV weight: with stand: 6.5 kg, without stand: 6.4 kg.
Attention! The LC390A2A panel of the HAIER LE39B8550T LED TV 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.