Chosen Solution
Tried power reset and other suggestions w/o results; I am quite handy and have a multimeter; it would be great to have diagnostic flow char (similar to an existing answer post but that was for xbr-75x850C). Thanks, Bai
Hi, With power connected to the TV there should be 3.3V DC on pin 5 of the connector, lower right side of the power board as shown in your image. Everything looks OK on the board i.e. no obvious damage and since you said that the main fuse is OK, without a schematic it will difficult as you would have to start checking if there are any voltages appearing on the “secondary” side of the board to know if the problem is on that side of the board or the high voltage primary side. There is a “Power On” pin mentioned on the board (same connector as the Stand by pin) but this is only to turn the power board fully on once the mainboard gets the signal to turn it on from the remote or power button. So there should be no other voltages on the connector on the secondary side except the 3.3V which is supplied to the mainboard.
Bai Gu your Klein tool will not work for this. You do need to get a simple multimeter (analog or digital will work) You need to measure the voltages on CN6401 of your power board and see which ones are present. Those are DC voltages. You need to have the STBY voltage. If you do not have that, it is your power board that is having problems. There is also a reason why this power board seems to be very difficult to come by. It is common that boards that are widely unavailable are those that are having a high failure rate. The xbr-75x850G can use the xbr-75x850F power supply.
