[TenTec] Delta 580 Outboard VFO

[Nick]

Good afternoon all.

I have a TT 580 Delta ca. 1979 vintage.  Although I've modded the RIT so 
I can operate split up to +/- 4kHz I've always missed having a second VFO.

So I have built a VFO for the purpose which seems stable enough, but am 
mystified by what A/B switching to build into it.

Does anyone have a schematic of the TT 283 remote VFO for this rig, so I 
can see how it was done originally?

73

Nick G3VNC