My 46-1209 has a 7n7 where the 7af7 should be. This radio has been in the family since new so should I keep the 7n7 or replace it with the correct tube
A 7N7 is a direct sub for the 7AF7. The only major difference is the 7N7 has a filament draw of 0.6 amps
vs 0.3 amps for the 7AF7. Is probably not a problem for your power transformer as tubes V4/V5 have a
seperate filament winding.