yes test the other connector cn102, test in standby(tv plugged in with power off) take note, then power up tv and take note, so with the red pos. probe on pin one check voltage, leaving probe in place power up tv check and see if it changes or anything, check all the pins, example pin 1, +18vsb1, power off 0 volts, power on 18 volts or whatever it reads.

try reseating the ribbon connectors at the tcon board and the lvds cable at the tcon board, might be bad connection might be a faulty tcon board.

my first thought is maybe bad capacitor/s on the powerboard.

could be a connection issue, try unplug and replug all the connectors a few times, then test it.

Are you using wifi or hard wired with ethernet cable?

If the cleaning doesn’t do the trick, maybe replace the pcv valve, about 5 bucks at the auto parts store.