Sony kdl-46xbr4 won't turn on with no blinking standby light

My Sony Bravia doesn't show any picture or sound with power LED staying green and Sony logo lit. When opened the back to clean, noticed no glow on backlights. No capacitors look bulged or burnt and there is normal relay click. Odd thing is, I don't get any blinks (Red) on standby light indicating error. FB1 has heartbeat so I thought TCON might be an issue but since I have no glow, I'm thinking driver board (DF2&3) or the inverter boards. Worst case bad panel. I've checked standby voltage along with 12v/6v references on DF2&3 and all look normal. I did notice no 3.3v inverter trigger on GF1 but not sure if it should be there if there is no video source (HDMI) is plugged in.

I did try to take power off DF2&3 at a time to see if I get panel to glow with some sort of picture on either side but nothing. Again, this is hard because I have no blinks on standby light. I'm leaning towards power GF1or AU board.

Any help in isolating the problem would be greatly appreciated.