[R-390] VFO endpoint adjustment - stumped!

[Tim Shoppa]

Thanks all - I have solved the PTO range issue!

First: that brass thing I was turning with the screwdriver was
the oven thermostat. Little to nothing to do with endpoint etc.!
Nobody here seems to care too much about the thermostat so I
won't worry much either (after I make sure that whatever I set
it to doesn't make the PTO cook itself!)

Second: the pictures of the disassembled VFO inspired me to take
mine apart. Took out the VFO, took off the mounting brackets,
took off the outer can, took off the oven (unsoldering 4 wires),
then I finally get to see the works.

No apparent bending/etc. on the inside. The two "limits" I was
feeling from turning the shaft came from the core hitting the end
of its travel (this is the high end, at approx 3.7 MHz) and something
else I never understood on the low side (which was stopping me at
2.5 MHz). Visual inspection showed that physically there was at least
2 and probably 3 more turns that the core could go in. So all I did was
crank the core to its outer end (where it emerges from the mechanism
if you remove the end), take it off, and put it back on one turn
earlier. Now the PTO covers 2.4 MHz through about 3.6 MHz, which
is great. Linearity is not as spot-on as it was before the intervention,
but now that adjustment seems trivial with a frequency counter
and whatever kind of tiny screwdriver fits those little screws.

Again, thanks everyone! Oh, and thanks for the confirmation that
I am not insane regarding 2.2K plate resistors. I am still astonished
that almost all of them in my radio were high by a few hundred percent,
while very few of the other resistors are out of tolerance.

Tim.