Chosen Solution
With a video input, I can see the array backlight move with the picture, but the LCD screen itself is black. Even on-screen menus don’t appear - the LCD is not functional. There are three boards in the signal path - the main board (BM1), the DPS board, and the Timing Control board. The fact that the backlight is active with video input suggests that the main board is fine, though the speakers don’t seem to work which suggests that it may not be. The DPS board sits between the main board and both the Timing Control board and the array backlight control board. I can find very little information on how to diagnose it. The Timing Control board has 12.6V at its power connector and the on-board fuse is fine. I have confirmed that the panel is not shorted. The links between each board are high speed digital, and I don’t have a logic analyzer. I’m not sure how to go about narrowing it down to which of the three boards warrants replacement.
Hi @hikeonpast The service manual (your model number seen on p.2) seems to indicate that the cable to the tcon board, the mainboard or the panel itself may be the problem Here’s the no picture troubleshooting flowchart from the service manual which may help. Having no audio also seems to put it back to the mainboard as it is not just a problem with the video section of the TV
@hikeonpast this “though the speakers don’t seem to work “ combined with your no video situation leads me to make the main board the number one suspect. Of course, you will have to check every video input source i.e. component, coax etc. and see if that makes a difference. Also, make sure that you disconnect any cable or sat boxes and try a local source like a game console/BR/ DVD etc.
