High plate voltage on 6L6GC

[angelodp]

I was seeing normal plate voltage on my 6G4 amp of 455v for the plate reading. I noticed that the cap on the intensity knob was leaking and the wrong value. Schematic calls for .05 and the amp had .02 . I swapped it out for a new PS series .05 and the the voltage readings at the plates climbed up to 470? I am also reading -59v at the control grid which is quite high. Hv checked resistors around the amp and they are good. Filtering at the bias board was hanged to higher values 50uf/150 but other than that its pretty much stock. Any thoughts on trouble shooting this. Amp plays and sounds pretty good.

[Structo]

What is strange is that you said the bias current was only about 18-20ma but your bias voltage is -59v.
The schematic has it at -55v so not too far off on yours.
It also shows a plate voltage of 456v so you are not too far off of that.

I don't see how changing that intensity cap would make the power tube plate voltage go up.

[angelodp]

Ok but the receiving manual shows a max of -37 for the Control grid but the schematic shows -55v as a correct reading.