Hi Chuck et al:
After running a few more hours, the noise just stopped, period. It
appears the hobgoblins hiding within have been routed. Maybe it was
more boiling away that was needed, maybe some piece of ancient dirt
got dislodged or maybe it ran out of gas. I guess we will never know.
If the problem should return, I'm armed now with the wisdom of your
replies. Thank you all!
As regards the bias resistor in the B- lead, I never had any problems
whosoever over the years with this. Now if I could think of a solid
state way of switching it in and out instead of my klunky T/R relay...
Any thoughts on that?
Best,
jerome VA7VV
On Wed, 11 Jun 2008 20:39:02 -0700, Chuck Lewis <n4nm@knology.net>
wrote:
> This is a timely question for me, too, since I'm considering making
> a modification to my Drake L-7, deriving cutoff bias from a resistor
> in the filament side, rather than the existing heat-producing
> voltage divider in the P.S. which would be disabled (yes, there'll
> still be a bleeder). The 120 VDC from the divider is currently also
> used to develop ALC, but my exciter is matched nicely to the amp,
> and I don't anticipate using ALC...therefore, Jerome's question
> raises an issue applicable to my planned mod: is there an unintended
> consequence associated with this approach to cut-off bias???
> Inquiring minds want to know...
>
> Chuck, N4NM
>
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