Help understanding servo motor

I have a couple of small servo motor pulls from a big plotter. On one end of the motor is a "gizmo" that has a few electronic components (mostly resisters, an LED, and clear plastic disk attached to the motor shaft, a couple of pots, and an 8pin chip marked with the Mitsubishi logo and the designation M393)

So.. I'm guessing this is the rotational positional counter gizmo (forgive me for not knowing the correct terms).

Anyway, can I use this? any tricks to figure out the pinout (looks like about 5 pins of a 10 pin ribbon cable are connected)

- jim