Since I got it - used - my MH871 has come up with 24 i/s and 100g. This has proven appropriate for everything I do. Suddenly, those settings changed on startup. I was able to change the force, but speed is stuck at 1 i/s and the buttons won't change it. I purchased a replacement board and installed it - no change. The cutter still works fine, but is obviously REAL SLOW. Thoughts?