[Premium-Rx] Harris RF-550 Electronic Tuning Help

[Keith Densmore]

Greetings,
Probably one of the earliest premies, I have a Harris RF-550 that has the
optional electronic tuning board installed called an RF-583 (up/down tuning
switches rather than thumbwheel decade encoders).  Problem is I can find no
information on this circuit board and I desperately need a schematic. The
regular Harris manual only carries the schematics for the original circuit.
Can anyone help with the '583 schematic??
Thanks, 73,
Keith ve3ts