[Collins] KWM-2 driver bias mystery & need K3

[Tim Nichols]

Hi.

I just became a first-time Collins owner (after 36 years of hamming!) with
an E-bay KWM-2 purchase. Having some minor problems getting it on the air
(bad C47 and an open coil on K3 -- not bad at all, really), but the most
curious situation is that my unit (SN 411 - early!) is completely missing
the V8 cutoff bias circuit. It was not removed; It apparently was never
there. The -70v (receive mode only) line is at the appropriate terminal
post, but nothing is connected to it (nothing has been unsoldered, as the
factory red paint on the joint is completely intact). There is no L11, no
C122 and no R103 and one of the terminals that this circuit should be
mounted on (per my 1978 version CCA-downloaded manual) is a "virgin" - it
has never had anything soldered to it at all.

My first question is whether I'm looking at a factory defect or was the V8
bias circuit added after my SN in one of those undocumented production
changes I've been reading about all day?

Second, is this one of those "leave it alone" situations or should I try to
restore the receive mode cutoff bias to the 6CL6? What, if any are the
disadvantages of not keying the driver?

Anyone have any explanations/ideas?

Oh, I also need a K3 replacement and really don't want to pay the Surplus
Electronics price. Anyone have one or know where I can find one or a
suitable substitute?

Thanks to all in advance.


Tim
N2TC