So the cassettes worked... sort of. I've verified my memory boards and servo board and MPU are all good. The cassettes load off the master and I can program in conversational. The problem is that the buttons on the control are... finicky at best. "Auto" "Start" "Check" "Enter" and "Single Cycle" all work maybe half the time. The spindle buttons, with the exception of the brake, are even less reliable. That pretty much seals it for me, time for a retrofit. I'll be selling off the memory, MPU, interface, CRT, Cassette reader, etc, and switching to LinuxCNC with the Mesa boards. Digging through the diagrams, it appears this control used a hodgepodge of control voltages, which may make my work a little more difficult. I have 5V, 24V, and ±15V. I really want to save the amps, servos, encoders and limit switches, everything else will go. Is there any build thread for a Hurco SM1, KM3, KM3P or KMB1 where the amplifiers were reused? I have a Mesa 5i25/7i77 kit, so I have analog control signals.