This is the little board that got Roland into trouble in the 1970s, a clone of the Moog VCF. It sounds really, really nice. I also own a later SH-2000 containing the revised filter, it does not sound really, really nice.
I had to replace the op-amp and electrolytic capacitors to bring this filter back from the dead, it was well worth it.
The filter is the middle part between both dotted lines. The left section is the noise generator and the right is a 3080 based VCA.