I just bought a Dw-6000, and I am sure it has not been tuned up in 30 years. Anyhow, on a flur pre-set DC01 level-0, DC02=0 but Filter Res=31, which means the sound is being generated by a self oscillating filter. It is badly off tune and wonder if there is a procedure to tune the VCF like you can on a JX-3P via the trim-pots. Has anyone tried this or have some info on this?????