Chosen Solution
I tried a lot - measured the power board with a multimeter, bought a new power board (KB116WJQZ), measured power supply, baked the motherboard in the oven - nothing, no standby light, no power. I’m not quite ready yet to give up on the TV, so does anyone have any idea what to try next? Thanks
@joejonson There has to be a voltage from the power board to the mainboard. Perhaps when the new power board arrives, do not connect any cables to it except the AC power cable and check for voltage on the PD connector pins, presumably only the AC Det or STB pins That way with no other cable connected to it, there’s nothing that can damage the power board. If there is none then the power board is not providing initial standby power to the mainboard for some reason Can’t imagine why especially if it happens with a 3rd power board, unless the board is shorting out to the chassis where it shouldn’t be i.e. not at designated earth point on the board through a screw connection but somewhere else where it may be touching the chassis.
