Weird issue with an RCA 730TV2

[Penthode]

Originally Posted by Kamakiri

Just to recap (har har), I have no raster on this set at this point but audio is fine, adequate HV (neon bulb test). Had a nice bright picture briefly, but doesn't now as outlined in the previous posts.

Usually at this point I'd start by measuring voltages working from the RF amplifier forward or going to the first video IF and working backward. Since I've got weird voltages right at the RF amp I'm kinda puzzled as to where to go from here.

Did you set the contrast control to minimum and then check the RF amplifier plate voltage??!! Check the grid bias: I suspect the 6J6 is conducting heavily and pulling down the plate voltage. RCA did not include agc until the '48 models hence the contrast control feeds the rf and if grid bias.