The LV rectifier filaments are usually on a separate winding.
Mainly because if it shorts H-K having 150V on the other
filaments is not a good day.
For the socket you can carefully remove pins from another
socket & replace a pin or drill out & replace the old one.
On some sockets you can also use a jewelers screwdriver
from the top & squeeze it tighter. Used that on tuners a lot
to save a rebuild.
For some filaments not lighting some sets use both a series &
parallel string or 2 series strings. Having more than one open
fil. tubes would be near imposable.
73 Zeno
