Regarding position sensing: not that simple! The controller decides
(mechanically) when rotation is complete. When you move the knob on the
controller, one part of the dial is under spring tension and a solenoid that
is controlled by a contact in the rotor itself allows the dial tension to be
released one "notch" at a time. When the two parts of the dial again line
up (meaning rotor is now in the direction you pointed), power to the rotor
is turned off. I suggest you try to find an old control box, and make sure
that the dial spring is not broken.

73, K8AC


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Hi Barry

Thanks for the info. I had originally thought there was a DC and it
was reversed by polarity. This is a more unusual setup, at least from
what I am familiar with. I find it hard to figure out how that
capacitor causes the reversal, but as long as it works. If I am
correct, this tells me that one wire is forward, on reverse and one
common (ground). That leaves the 4th. Let me guess, that one
controls the indicator position, and I would guess thru some sort of
resistance variation ???? The rest and what you explained makes
sense.

I recall trying to find some of those non-polarized caps for a speaker
crossover setup. Not easy to find. I never know about using two
standard caps in that manner.

PS. How would I determine which is the common wire? I would assume
the other two dont matter, it either turns one way or the other. The
4th, I am not sure how that one would be determined.
George