These sets are only able to be activated by infared remotes and dont
have the over the cable remote activation features. Once activated only
chan vol and cc funtions can be accessed.
Also I have a number of the same model purchased at the same time as
the others that are working fine.
And these TVs worked fine for a couple years until they developed the
problems
Now I am not ruling out a chip problem since the problem will either go
away after being on for a few min or do the opposite and fade away
after a few min. But the most common problem seems to be the come on
for a second full brightness then dim down to a either very dark
picture or completly black.

I contacted PDI and they are pointing me to a capacitor but after
changing it out on 1 of the TVs (only had 1 cap lol) the problem didnt
change.

Oh well back to proding and tracing to try to track it down with my
poor schematic lol

Thank you very much for your responce, I appreciate any thoughts.