Issue with my TV:
1. The standby red LED continuously flashing red with dark screen. Pressing the power button manually or from the remote has no effect
2. When and if all the cables are connected, the display is dark, nothing appears on the screen.
3. The flash light test of the LCD display does not produce any images that is because there is no power reaching the LCD from the Tcon board.
4. The Tcon board gets no power at all on pins 47 to 51 (according to the legend) of flex cable from the MB, expected 12 to 13V. The fuse on the Tcon is NOT open, I verified. And there are 3 LEDs on the Tcon board, none is lit, supposedly blue. Again, the Tcon board does not get power from the MB board therefore, I do not expect these blue LEDs to light up.
5. The Main logic board gets the 13VDC from the PS. I am very confident the PS has no issue given I verified all the voltages with and without load (cable to backlight LEDs and cable to to MB).
6. If I disconnect the flex cable from MB to the Tcon board, the backlight LEDs start flickering at the same frequency as the flashing red light, appears that way anyway.
7. If I disconnect the power cable from PS to the MB, the backlight LEDs will light up and say lit with Blue screen while the standby red light still flashing
8. Disconnecting the speaker and power board/IR board from the PS has no effect.
9. Here are the voltage readings on the PS plug to the MB:
Again, pressing power button has no effect but the PS to MB makes a bit of a difference on some readings, the Even pins [2,4,6]:
Connector CNM803 - PS <---> MB. All measured Voltages:
(Even Pin#)
All Cables connected PS <---> MB Disconnected
2 OD/UD 0.1 - 2.47V 2.29V
4 BLU ON/OFF 0.0 - 0.15V 3.3V
6 PS ON/OFF 0.0 - 3.30V 4.46V
8 GND 0.0 0.0
10 GND 0.0 0.0
(Odd Pin#) - same values when all cables connected and disconnected.
1 A13V 12.12 - 12.77V
3 A13V 12.1 - 12.77V
5 A13 12.1 - 12.72
7 A13V 12.1 - 12.72
9 GND 0V
My observation is that the CP or BGA on the MB keeps resetting probably on Pin 6 (PS ON/OFF). I did back trace pin 6 and 4 with some measurements on the MB but could not find anything shorted or open, at least nothing obvious. And nothing charred or burnt on any of the boards.
Also, I heated the BGA with hot air gun for 3min and did not make any difference.
All indications point to the MB but I am more interested in figuring out which component (s) is faulty. Replacing a whole board takes the fun out of it and frankly not worth the cost given how expensive they are. So any help or pointers much appreciated. Thanks
1. The standby red LED continuously flashing red with dark screen. Pressing the power button manually or from the remote has no effect
2. When and if all the cables are connected, the display is dark, nothing appears on the screen.
3. The flash light test of the LCD display does not produce any images that is because there is no power reaching the LCD from the Tcon board.
4. The Tcon board gets no power at all on pins 47 to 51 (according to the legend) of flex cable from the MB, expected 12 to 13V. The fuse on the Tcon is NOT open, I verified. And there are 3 LEDs on the Tcon board, none is lit, supposedly blue. Again, the Tcon board does not get power from the MB board therefore, I do not expect these blue LEDs to light up.
5. The Main logic board gets the 13VDC from the PS. I am very confident the PS has no issue given I verified all the voltages with and without load (cable to backlight LEDs and cable to to MB).
6. If I disconnect the flex cable from MB to the Tcon board, the backlight LEDs start flickering at the same frequency as the flashing red light, appears that way anyway.
7. If I disconnect the power cable from PS to the MB, the backlight LEDs will light up and say lit with Blue screen while the standby red light still flashing
8. Disconnecting the speaker and power board/IR board from the PS has no effect.
9. Here are the voltage readings on the PS plug to the MB:
Again, pressing power button has no effect but the PS to MB makes a bit of a difference on some readings, the Even pins [2,4,6]:
Connector CNM803 - PS <---> MB. All measured Voltages:
(Even Pin#)
All Cables connected PS <---> MB Disconnected
2 OD/UD 0.1 - 2.47V 2.29V
4 BLU ON/OFF 0.0 - 0.15V 3.3V
6 PS ON/OFF 0.0 - 3.30V 4.46V
8 GND 0.0 0.0
10 GND 0.0 0.0
(Odd Pin#) - same values when all cables connected and disconnected.
1 A13V 12.12 - 12.77V
3 A13V 12.1 - 12.77V
5 A13 12.1 - 12.72
7 A13V 12.1 - 12.72
9 GND 0V
My observation is that the CP or BGA on the MB keeps resetting probably on Pin 6 (PS ON/OFF). I did back trace pin 6 and 4 with some measurements on the MB but could not find anything shorted or open, at least nothing obvious. And nothing charred or burnt on any of the boards.
Also, I heated the BGA with hot air gun for 3min and did not make any difference.
All indications point to the MB but I am more interested in figuring out which component (s) is faulty. Replacing a whole board takes the fun out of it and frankly not worth the cost given how expensive they are. So any help or pointers much appreciated. Thanks
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