Litzendraht wrote:
Yes, they are just coils that are enclosed in ferrite pot cores to
make them "Hi-Q". You have found the threaded rods sticking out each
side. This is how you vary the frequency of each coil.

The last time I fooled with it, I recall that it had a pretty wide
tuning range up and down from 230 kc. Each coil winding has a dipped
silver mica cap across it's terminals underneath. I can't imagine those
caps drifting in value.

It is probably seeing the same problem that has been showing up in VFO's
for R390's. It would appear that after enough time has passed, the ferrite
changes its characteristics, and the VFO can no longer be adjusted to be
linear across its whole range.

-Chuck