OK, so on each tube socket, Pins 5 and 6 measure 330 Vdc with respect to ground? And, the two LEDs on each C4S are lit? And, the only tube pin you worked on during the installation was Pin 5?
Have I got all of that straight? If so, I would double check that each lead on the C4S is going where it is supposed to, and that each transistor is correctly oriented.
I must admit, though, I am still stumped about how that Voltage can be getting to Pin 6 on each tube.