This is a truly unique Moog Prodigy! I purchased it on ebay, broken, about a two years ago. After restoring all of its original functionality and its original appearance, I realized it held a lot of potential for interfacing with other modular equipment, including my EML101.
Luckily, this was the later model with the Sync Input, VCF Cutoff In, Oscillator In, Keyboard In/Out, and S-Trig In/Out.
I added a Gate Input, Gate Output, Oscillator 1 Output, Oscillator 2 Output, Mixer 1 Input, and Mixer 2 Input.
The 'Mixer Inputs' come before the Mixer potentiometers, so (one or two) external signals can be injected, attenuated, and mixed.
The Oscillator Outputs are interesting, too, because they act as effect send/returns. For example, one oscillator can be run through a phaser or vibrato effect, while the other is left dry.. and they both run through the VCF and VCA.
In lieu of drilling and adding a VCF FM control pot, the Oscillator Output jacks make it possible to patch the audio frequency CVs to the VCF Cutoff Input with a simple attenuator in between.
I built an additional unit to serve as the Prodigy's second LFO, Noise Source, and Patching Attenuator.
Due to financial constraints, I had to sell this Prodigy on ebay about a year ago. I vowed to one day build a cloned VCF (so the EML101 could impersonate the Moog sound).
Here are some sound samples (recorded with the additional module for modulation, noise, and/or patching.. and some spring reverb):
E-mail me if you'd like to have your prodigy modified similarly!