Thursday, 16 January 2020

REPAIR / SERVICING TV SAMSUNG UE46B7020



Technical description and composition of the SAMSUNG UE46B7020 TV, panel type and applicable modules. The composition of the modules.
SAMSUNG LED
Model: UE46B7020 UE46B7020WW
Panel: LTF460HF08
LED backlight: LJ64-01765A, LJ64-01764A, LJ64-01763A, LJ64-01762A
T-CON: 2009FA7M4C4LV0.9
LED driver (backlight): integrated into PSU
Power Supply (PSU): BN44-00269A
PWM Power: MC33067P
MainBoard: BN41-01190B BN94-02706W
IC MainBoard: WM8593SEFT, RTL8100CSL, K4T1G164QE-HCE7
Tuner: BN40-00145B TDHG6-K13A
Technical Specifications UE46B7020WW
SAMSUNG UE46B7020
General repair guidelines for TV LCD LED
Possible malfunctions
- SAMSUNG UE46B7020 does not turn on at all and does not show any signs of operability. Does not blink indicators and does not respond to control buttons.
In most of these cases, the main switching power supply BN44-00269A is found to be faulty. It is necessary to measure its output voltages and, if they are absent, to check the short circuit probability in the converters power switches and rectifier diodes.
In the event of a breakdown in the secondary circuits of the converter, it can usually fail in short circuit mode, and in the event of a short circuit in the power elements of the primary circuit, the main fuse or current sensor at the source of the key most often breaks.
Mos-Fet keys used in switching power supplies usually fail due to a malfunction of other elements that can put it out of operation in key mode or provoke an excess of the maximum current or voltage. It can be supply, damper circuits, or elements of OOS (negative feedback) stabilization. The reason for the breakdown of the power switch may be PWM (MCW) MC33067P. It is checked only by replacement with a known good one.
- There is no image, there is sound, it responds to the remote control. Or the image may appear for a second when turned on and immediately disappears.
In most cases, a malfunction is caused by a lack of display backlight. The reason for this may be a break in the LED circuit, or a problem in stabilizing their power supply.
To check the health in the LED circuit, it is better to use a current source with a maximum voltage of 200V. We do not recommend using any voltage sources for this purpose. You can test each LED individually with a simple Chinese multimeter (powered by 9 volts) in the P-N-junction test mode. If you connect the red probe of the multimeter to the anode of the LED, and the black to its cathode, then the 3-volt LED will light up slightly, and in the opposite direction you can detect the transition of the emergency zener diode. A zener diode PN junction indirectly indicates a LED-a
- The TV does not turn on, the indicator signals standby or working mode, or blinks.
Repair or diagnostics of the BN41-01190B motherboard should begin by checking the stabilizers and power converters needed to power the microcircuit and matrix. If necessary, you should update or replace the software (software). In cases of complex repairs of MB (SSB) and in the presence of the necessary skills and equipment, sometimes it may be necessary to replace its WM8593SEFT, RTL8100CSL, K4T1G164QE-HCE7 chips and other possible faulty components. Malfunctions associated with the application of BGA soldering technologies are usually easily diagnosed by the heating method.
If the TV works normally from external devices, but does not tune into television channels, the tuner BN40-00145B TDHG6-K13A may be malfunctioning. In such cases, first of all, you should make sure that there are supply voltages at its corresponding terminals. It is also necessary to make sure that the tuner and processor can exchange data via the I2C bus. Sometimes the cause of the inoperability of the tuner may be a software failure.
TV users and owners need to remember that attempts to self-repair a SAMSUNG UE46B7020 TV without the appropriate qualifications and necessary experience can lead to serious negative consequences!
The appearance of the MainBoard BN41-01190B is shown in the figure below:
BN41-01190B
BN41-01190B can be used in TVs:
SAMSUNG UE40B6000VW UE40B6000 (Panel LTF400HF08), SAMSUNG UE46B7000WW UE46B7000 (Panel LTF460HF08), SAMSUNG UE46B6000VW UE46B6000 (Panel LTF460HF08), SAMSUNG UE46B7020 UE46B7020WW (Panel LTF460HF08).
The appearance of the power supply
Main features of the SAMSUNG UE46B7020 device:
Installed matrix (LED-panel) LTF460HF08.
The matrix control uses the Timing Controller (T-CON) 2009FA7M4C4LV0.9.
To power the backlight LEDs, a converter is used, combined with a power supply.
The formation of the necessary supply voltages for all nodes of the SAMSUNG UE46B7020 TV is carried out by the BN44-00269A power module, or its analogs using MC33067P microcircuits.
MainBoard - the main board (motherboard) is a module BN41-01190B, using microcircuits WM8593SEFT, RTL8100CSL, K4T1G164QE-HCE7 and others.
The tuner BN40-00145B TDHG6-K13A provides the reception of television programs and tuning to channels.
Additional technical information about the panel:
Brand: SAMSUNG
Model: LTF460HF08
Type: a-Si TFT-LCD, Panel
Diagonal size: 46 inch
Resolution: 1920x1080, FHD
Display Mode: SPVA, Normally Black, Transmissive
Active Area: 1018.08x572.67 mm
Frequency: 60Hz
Lamp Type: CCFL
Signal Interface: LVDS (2 ch, 8-bit)