Successfully built a Music Thing Modular Turing Machine Mkii and its Volts expander (which indicates faults in the assembly). Only four steps of the expander produce changes is the voltages which indicates bad solder joints, a problem with the 4015 chips, an issue with the clock input (using Ginko Synthese LFOv2), the pcb or something else. Checked all of the solder joints but they look good. I’ll have to get new chips, reheat all the joints and try again. The issue seems common and similar behavior is described on a Muffwiggler thread. Forgot a 10k resistor from Volts, soldered it down and everything works now!
Eero Yli-Vakkuri