[R-390] WTB BFO module

[David Wise]

I'd like to borrow or buy a BFO module.  Yes, I
know Fair has them; I thought I'd ask here first,
in case you have a surplus.
I'm in Hillsboro Oregon, which is near Portland.

My BFO flatlined this weekend.  It's not the tube,
I tried half a dozen subs.  B+ is getting through,
the tube's just failing to oscillate.  It's not the
resistors, they're all in spec at operating current.
It's not the external caps, not even the two micas.
The only caps I haven't checked are the two
50pF temperature-compensating ceramics
inside the housing.  (The 1600pF "doorknob"
reads perfect on my impedance bridge.)
When I inject a swept 455kHz signal at the
cathode and monitor the grid, I can see a peak,
with a voltage gain of about 25, and when I turn
BFO power on, it sharpens noticeably as the
tube regenerates.  But it looks like the Q is too
low to meet the Barkhausen criterion.  I resoldered
all connections and loosened and tightened the
two screws that form part of the tank circuit wiring,
no change.  I think the 60uh fixed autotransformer
has shorted a turn.

Thanks,
Dave Wise