My fabscan-pi kit came with a 200 step motor (17HS8401). I'd like to upgrade to a 400-step motor, but don't know what to choose... There apparently is a 17HM8401 that looks promising, but I want to be...

Sorry to bump an old thread, but I'm getting the same "local variable 'ret' referenced before assignment" error as the OP. My laser is working, but I'm a complete noob here. This error is what I'd exp...