B.B. wrote:

All six wires go all the way to the gyro--there don't seem to be any
sort of sensors on any of the bearings.

Right, this is not a closed-loop gyro where servo amplifiers control
torquer motors on the gimbals. It is just a free gyro.
The delta-shaped arrangement looks like it may be a transformer or a
bunch of inductors.
That is the flux gate. The earth's magnetic field passes through the
iron in those flux gates and is picked up by a sensor. There is some
procedure where every hour or so you read the flux gate and realign
the gyro's remote indicator with the earth's magnetic field.
Of all three rectangular objects, each has two
metal plates going through in parallel and the wires going in go into
the jacket. I can't tell if the two strips are connected, but I don't
think they are.

The two large capacitors are in parallel. Both ends are tied to
wires that go into the gyro housing.
Yes, these are the phase shift capacitors that allow the motor to run on
single-phase power. From the motor, there should be one wire that runs
straight to the connector. Another external wire goes to the motor, but
also to the capacitors. And, finally, there should be one motor wire
that just goes to the capacitors. The external wires should have
connectivity to capacitor terminals. And, these should show no
connectivity to any other wires.
One wire from the gimbal feeds to
one of the the capacitors, but all the rest go through the delta thingy.

Yup.

Of course, you still have the problem of coming up with 400 Hz
single-phase power.

Jon