No TV techs here so I'll share the usual.
a few weeks ago, my LG tv went to a lighted blank screen, no audio, after adjusting volume, or mute. You would click the power button, and after ten seconds, tv would turn off. You turn it back on, tv picture and sound fine, for a while until it happens again. I opened up TV and saw one bad capacitor on the power board, which I replaced. No difference. I replaced another 12 caps, same thing. Yesterday, tv went to blank screen continuously, replaced last 6 caps today, nothing.I checked power supply voltages at strip, all there, with good grounds. Any ideas?