Sony KDL-40XBR9 green led no video or audio

[keats11]

I picked up this TV from CL. The TV had been opened, and I was told the Sony Techs diagnosed it as needing a main board which they couldn't find. I got it home, when I first powered it on, the words BRAVIA flashes for a second and the backlights stay on for 20 seconds, but no video or OSD. The backlights then turned off. All this time, the green LED in the front stays lit. If you hit the power button again it turned off, and iif you hit again, then it turns on, except, this time there is no "BRAVIA". Just a blank screen with backlight behind it. I got rid of the old main board and bought a new main board (yes I know it really is the main board, part number A-1728-743-A). With this board in place, now all the same behaviour repeats, except, now there is no BRAVIA that flashes either. Just a lit screen initially, followed by the BL turning off followed by nothing. If u try to turn on again, no BL this time, and green LED stays lit. The voltages from the PSU are all correct, 12Vunreg, 12V reg and 15V. I measured the voltages on some of the connectors, and in particular noticed that when the BL shuts down and the TV goes into a "coma" the inverter_err pin gets set to 1.9V (normal=0). At this point I do not know what the hell is wrong with this TV. If anyone has any experience with this set please help out. I have attached a picture of the boards.

[keats11]

Re: Sony KDL-40XBR9 green led no video or audio

Picture attached. Had to resize.

[budm]

Re: Sony KDL-40XBR9 green led no video or audio

Here is the service manual:

It is strange that you do not get any error codes either.

[keats11]

Re: Sony KDL-40XBR9 green led no video or audio

I did download the service manual, but that didn't seem to have any useful information about this problem, primarily because it doesn't throw any error codes.