The Casio MT-30 project (earlier details below) is 95% completed.
After stripping it down and giving it a good spruce-up I replaced all the noisy pots and switches. The new pots are smaller and smoother than the previous and the new switches have a more positive 'click' action. I had to remove the internal speaker to accomodate the new circuitry and I also removed the old (unreliable) rear phono output socket and replaced it with a regular jack socket. Same procedure with the old DC input socket.
The newly included ring-modulator is the only thing I'm not entirely happy with. At the moment both the carrier and modulator are being fed by the MT-30 audio so it acts more like a kind of harmonic octave shifter (upwards). But I've left a hole on the rear of the case to take a switched jack socket for feeding in external audio (an oscillator, or whatever) to the modulator input, which should be fun.
The newly refurbished and further modified Casio MT-30 keyboard.
The internal speaker in the photo below was removed to accommodate the new circuitry.
Close-up view of modifications in top right panel.
Includes: the fixed/variable master clock, tune, primary octave switch, variable digital distortion, ring-modultaor balance and a psuedo/semi random function.
Close-up view of modifications on the left end column.
Includes: 'quick' memory select function, secondary octave switch, vibrato rate (slow or slower), vibrato depth (none or shallow) and hold.
All these modifications work in addition to the existing Casio controls.