Ok, so most brightners just increase filament voltage, with
that in mind I made a voltage doubler, then ajusted a series resistance
till I ended up with 8 vdc across the filiment of the crt.
Now I can see the screen with the room lights on !, a vast improvment,
for as long as the decrepit 14bp4 lasts.
Anyone got a crt for sale ????, please let me know.
Bob R.