Spica Servo Subwoofer

I have two Spica TC-50 loudspeakers (serial number 1066), a Spica Passive Interface and a Spica Servo Subwoofer. I got all of that from my old college roommate when I bought his system back in the late 1980's.
The Spica Servo Subwoofer quit working recently. Would someone please suggest where I could get it fixed? I live in Wichita, Kansas and would like to keep it close to home. However, I am willing to ship it to a qualified technician or repair shop if necessary.