Hi everyone, today I'm working on this Samsung UN55F6300AFXZA. The stand-by light is not illuminating and the TV appears outwardly unresponsive. I tested voltages first with the MB hooked up to the PS then unhooked. The backlights all come on when the MB is unhooked from the PSU and all the voltages appear to come up to at or very close to what is on the board.
Here are the voltage readings:
Pin no/descr…………………..V w MB plugged in………….. V with MB unplugged
1 B13V………………………….. 0………………………………………12.67
2 P_DIM…………………………0 ……………………………………...12.67
3 B13V……………………………0………………………………………12.67
4 NC
5 Vamp…..………………………0 ………………………………………12.67
6 BLU_ON…………………….…0 ………………………………………2.98
7 Vamp…………………………..0 ………………………………………12.67
8 GND…………………verified to chassis
9 GND………………… “ “ “
10 GND………………. “ “ “
11 B5V…………………………….0 ………………………………………5.3
12 A5V…………………………….5.29………………………………….5.3
13 B5V…………………………….0 ………………………………………5.3
14 PS_on……………………… 0.24 …………………………………3.31
I suspect the main board is where the problem lies, so I traced the stand-by pin on the main board to IC1201 which is Weltrend Flat Panel Display Control Sub-MCU 61P8-RG480WT(LQFP), in particular to pin 22 (DSDA1) where 5V is present.
CN1201 is the connector from the P-JOG switch and wi-fi module. PIN 11 of CN1201 appears to be the high/low circuit for the power button. There are about .27v present at pin 11 until the power button is activated and the voltage drops to zero until the power button is released.
Furthermore I traced the PS_on pin to IC208 which is an AlphaOmega AOZ3018PI, 5A synchronous buck regulator. The PS_on pin traces through a couple resistors in series which appear to be working, about 4800ohms through both. From the last resistor in-series I get continuity direct to pins 2 (Vin), 3 (AGND) and 8 LX(sense) pins. There is no voltage present on any of its pins.
I traced this down as far as I think I can for the present, so I'm hoping for some guidance from here.
Here are the voltage readings:
Pin no/descr…………………..V w MB plugged in………….. V with MB unplugged
1 B13V………………………….. 0………………………………………12.67
2 P_DIM…………………………0 ……………………………………...12.67
3 B13V……………………………0………………………………………12.67
4 NC
5 Vamp…..………………………0 ………………………………………12.67
6 BLU_ON…………………….…0 ………………………………………2.98
7 Vamp…………………………..0 ………………………………………12.67
8 GND…………………verified to chassis
9 GND………………… “ “ “
10 GND………………. “ “ “
11 B5V…………………………….0 ………………………………………5.3
12 A5V…………………………….5.29………………………………….5.3
13 B5V…………………………….0 ………………………………………5.3
14 PS_on……………………… 0.24 …………………………………3.31
I suspect the main board is where the problem lies, so I traced the stand-by pin on the main board to IC1201 which is Weltrend Flat Panel Display Control Sub-MCU 61P8-RG480WT(LQFP), in particular to pin 22 (DSDA1) where 5V is present.
CN1201 is the connector from the P-JOG switch and wi-fi module. PIN 11 of CN1201 appears to be the high/low circuit for the power button. There are about .27v present at pin 11 until the power button is activated and the voltage drops to zero until the power button is released.
Furthermore I traced the PS_on pin to IC208 which is an AlphaOmega AOZ3018PI, 5A synchronous buck regulator. The PS_on pin traces through a couple resistors in series which appear to be working, about 4800ohms through both. From the last resistor in-series I get continuity direct to pins 2 (Vin), 3 (AGND) and 8 LX(sense) pins. There is no voltage present on any of its pins.
I traced this down as far as I think I can for the present, so I'm hoping for some guidance from here.
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