The MKS-30 Planet S is commonly referred to as a rackmount JX-3P, although it really shares its heritage with the GR-700 guitar synth. The MKS-30 has several advantages over the JX-3P, including simultaneous use of the PG-200 programmer and MIDI, a cartridge slot for storing an additional 64 patches, and velocity response.
The voice architecure is identical to the JX-3P. The two digitally clocked oscillators use a master clock which is divided by an even integer to achieve the desired pitch. This method never allows the oscillators to produce a pure pitch across the entire range, and is probably accountable for the MKS-30's somewhat cold sound. The two oscs can be synced together or cross modulated using the METAL setting. I'm not sure what actual process is used, but it definitely sounds metallic. The filter module is the same one featured in the Juno 106, and has both a resonant low pass filter and a variable nonresonant high pass filter. Only one shared envelope is available for VCA and VCF. The LFO provides sine, square, and sample and hold waveforms, and has variable rate and delay.
The PG-200 is the dedicated programmer interface for the MKS-30, JX-3P, and GR-700. The programmer communicates with and is powered by the synth via a 6 pin DIN cable. The PG-200 provides knobs and switches for all parameters such as DCO, VCA, VCF, envelope, and LFO. Unlike the JX-3P, the programmer and MIDI can be used simultaneously with the MKS-30.

Note: To simulate pulse width modulation on the MKS-30 select osc SYNC, route LFO to osc 2, and turn the MIX to 100% osc 2.

Another Note: To reintialize the first 32 patches in the MKS30 press and hold the WRITE button followed by the BANK button. The display will read COPY as the patches are copied into the first 32 RAM locations.

MKS-30 Schematics
MKS-30 System Upgrade