Reposted because reflector archives deleted the
orignal message after the first day.
I love both of my model 301 remote knobs for
my two OMNI VI+s. I am considering a modification
to the OMNI VI which would let me use the knob
to tune the RIT/XIT.
In order for this mod to work, I need to know a
couple of things. First, I seem to recall hearing
that the encoders for the main knob and the RIT/XIT
are identical. Is this in fact true?
Second, the logic board schematic (where the
encoders terminate) show that both the main
and remote encoders go directly to the 4077
XOR chips while the RIT/XIT one goes first
to a schmidt trigger chip for "cleanup".
This encoder is also connected through
pullup resistors to the +5v line, while the
other encoders are not. Does anyone forsee
a problem with merely using a 4PDT relay to
switch the input to the schmidt trigger chip
from the internal RIT/XIT encoder to the
external remote encoder? I plan on sensing
the LOCK led to drive the relay. The underlying
idea is that when staying on one frequency
I could LOCK the main frequency and then use
the external knob to tune in the various callers
when the RIT control is activated.
Terry Zivney, N4TZ/9