Those were quite advanced instruments in their day, possibly the very first I remember in a mass-market bass. They were well made and I had one of the last models in Ibanez' Polar White, that gorgeous white pearl they offered. I do remember a few ash tops, reminiscent of their Artist guitars of that era. They were wonderful basses for their day, and perfectyl usable still today.
I unfortunately also remember they were a bit noisy. I'm convinced that they were like this as these were usually high-impedance pickups hooked up to a powered, active tone network, which sucked in any pickup noise the minute you were in a noisy environment. I have no idea how to fix this on the bass, but outboard you could try a good noise gate.
J o e y