I suspect that a couple of pages is missing: those describing the cabinet, therefore, is there
anybody out there got those pages, please tif and zip them and send them to me. I will include
them in this pdf.

The PCB¥s are probably not in scale in the pdf document.

This is the missing text from page 26:

HOW IT WORKS
Voltage Controlled Amplifier
The voltage controlled amplifier is constructed around the MC1496 integrated circuit. This is
a balanced modulator - demodulator, the internal circuitry of which is shown in fig. 37.
The 1496 has differential outputs, i.e. two outputs in antiphase, which are not referred 
accurately the 0V line. A buffer amplifier (IC3) having differential inputs, is therefore used 
to provide a single ended output.
In fact the 1496 has two sets of differential inputs, one set biased at about 0V, and another 
set biased at approxiamtely -3V.
The input signal is injected into one of the -3V biased inputs (pin 1) whereas the control 
signal is fed to the other input (pin 8).
When using the circuit as a VCA, the maximum possible attenuation is required when the input is
0V. However, due to tolerance variations, the 0V from other modules may be up to 20mV in error.
Hence a rectifier, IC1, is used so that any voltage less than +50mV is regarded as 0V. The
maximum attenuation at 0V control, is adjustable by RV1.
When the module is used as a ring modulator the control signal is ac coupled and the output
will be the product of the two inputs.

 
HOW IT WORKS
Envelope Control
This module is simply a combination of a Transient Generator Type 1 and a VCA, both of which have 
been described previously.
The only modification to the transient generator is the deletion of the hold-level switch and
R25. (A hold level equal to the keyboard voltage is not required in envelope control).
The VCA is simplified by the omission of the rectifier (IC1) as the input is coupled directly
from the output of the transient board and any zero error may be nulled out by the RV1. In
addition the output potentiometer is not required and is therefore deleted.