[R-390] wow... the R-391A does exist - Video Update

[Barry Hauser]

> Cool video.
>
> I can understand the mechanisms spin back to 0,0 (or 0, -0.9xx), but what
> stops each shaft at the desired frequencies?  How do you "program" a new
> frequency?
>

It's a bit difficult to describe how it stops -- Each of the MC and KC is 
linked to a positioning head that contains pawls -- spring loaded things 
with hook shaped ends which catch into notches in disks.  Beyond that, maybe 
Paul can describe it.  Bear in mind, all of this is external to the deck and 
PTO arrangement which are standard R-390 stuff.

To run the autotune, you have to tighten both locking keys on the MC and KC 
knobs by turning them clockwise until tight.  The autotune should never be 
run without the locking keys tightened or it will un-synch the thing.  When 
they're loose and you can manually tune, you are changing the setting of 
whichever channel position is showing through a little window on the front 
panel -- that's how you program.  If you want to change another channel's 
frequency setting, you first tighten the locking keys and then turn the 
channel selector knob to one of the other 7 positions.  The "difference 
condition" in the control module (couple of relays, rotary switch logic and 
the little wheel with the channel numbers that show through) . triggers the 
autotune to cycle and go to the other channel you just chose which will be 
the last frequency to which it was set.  Then you loosen the keys and change 
frequency for that channel.

Hope that part is clear.  ;-)

Barry