Ken Stone/1973 classic Serge/Serge comparator and Schmitt trigger

The following info on the 1973 variant of the Serge comparator and Schmitt trigger module is presented for educational/historic purposes only and are not to scale.

Construction
PCB connections
 * A = 3 + input
 * B = 3 ramp input
 * C = 3 output
 * D = 2 + input
 * E = 2 ramp input
 * F = 2 output
 * G = 1 + input
 * H = 1 ramp input
 * I = 1 output
 * J = Schmitt input
 * K = Schmitt output
 * U = not used (0v)
 * W = 0v
 * Y = +6v

CC-BY-NC
Readers are permitted to construct these circuits for their own personal use only. Serge Tcherepnin retains all rights to his work.