I had an unusual failure mode on my BC-348-N.  The BFO quit, and all else was fine so it could not be the tube, or so I thought.  So I swapped out the BFO coil from a badly hacked BC-348-J I was still working on.  BFO still did not work.  Turned out that BFO oscillator tube is also the detector and that section was still working fine.  However after another hour or less the detector quit working as well and the fact it was the tube became obvious.  I had never considered that tubes could fail by section.

 

And I now have a BC-348-N with J BFO coil and vice versa.

Wayne

WB5WSV