#1
does anyone know how you identify which pins on a tube socket are the plate resistor pins?
#2
Type a search for valve type (eg EL34) into google and download the data sheet. This will tell you which pin is which, pin 3 is the plate in the case of an EL34. Look at the bottom of the valve socket (as you look into the chassis) the pins are numbered clockwise from the "key".
If you're hazy on this or are not sure what you are doing then please don't go messing around in there.