[Johnson] Ranger 1 Question/Problem

[Jim Brannigan]

The conventional wisdom ( in all the on line literature) is to move the
Ranger VFO VR dropping resistor to the OUTSIDE of the VFO box.
I have done so, but the Ranger is still on the bench so a change is not a
big deal...

What is the new "conventional wisdom"?

Jim


> Makes sense to me, Glen. I don't relocate them anyway, I just change out
the
> original carbon unit with a 7.5 watt 18K Dale wirewound, and that seems to
> work just fine. Doesn't change the wattage inside the VFO cage, just
spreads
> it out a little. Ha. Hope folks don't get the idea they don't have to do
> anything about R3, though. It will fail for certain someday, and it's
> failure mode will invariably be decreasing R, with a resultant increase in
> load on VR tube, and concurrent increase in I as the poor overworked VR
tube
> works it's little guts out trying to keep up, which of course increases
the
> current through R3 again, which increases the heat, which increases rate
of
> R decrease, ad infinitum. A classic vicious circle, and the eventual
result
> is not pretty, as documented by some photos floating around the web.