I found one of them. Let me describe the rear of the instrument to you and
see if it matches what you took out of your aircraft.

There are two adjustment controls on the rear. The top center one is
labeled LOC and the bottom right one is labeled VOR.

In the lower left corner there is what we call a "cannon" plug, about 1.25"
diameter and with 14 male pins inside the plug housing.

That what you've got?

Now, as I said, this one was working 20 years ago when I took it out to
replace it with the RST navcom(s). If it is DOA when you get it, start
thinking that perhaps it is the radio that drives the heads rather than the
heads themselves. What radio is driving the head?

If the radio is good, and this one doesn't work, I'll look around for the
other head.

Jim


"RST Engineering" wrote in message
...

I've got two old VOA-4 heads sitting SOMEWHERE