Tom Sendall asked about the unknown control lever on the Symphonion
musical box.  Well, Tom, you are correct.  That is a tempo control.
A little careful re-bending should put it back in the correct location
and restore its function.

It is supposed to rub on the shaft of the governor in the smooth area
just above or below the fan.  At one extreme (fast), it should be just
away from the shaft and at the other extreme (slow) it should touch the
shaft and apply a small force resulting from the springiness of the
wire.  A small amount of oil on the felt will keep the shaft from
rusting where the felt touches it when it is left engaged.

Regards
Craig Smith