hi!
sorry for being so imprecise; the Arduino environment is 1.8.2 under Ubuntu 16.04 (it did not work with the Arduino IDE on the Raspian Stretch I have installed, too); I had an older version (from this april) where a sketch was still uploaded, and there to motor started to spin. now it doesn't after uploading this sketch - so far to the "not working" thing. the installed version of the AccelStepper library is 1.57 ...
yours
wolfi