I picked up my old TV from my basement which I havent used for a year, powered it on, the screen lights up but it is blank with no audio or video output.
The model is a Panasonic TC-L47E50 LCD.
I haven't done too much testing or diagnosis, because I think the problem is not the internal power supply but potentially a problem on the T-CON board or the secondary board(s).
One of the caps measured 300V 10 minutes after unplugging and showed no signs of discharging and some diodes seemed to be shorted (diodes normally allow 1 way power flow only, but this ones seems broke)
Could it be a power supply problem, or a much more complicated T-CON board or other board problems?