I am having some trouble with our SL-20 lathe (as usual). I keep getting Alarm 235, the spindle encoder has already been replace twice. The last one was replaced about 1 month ago and the machine ran ok until today, I cant even get through 1 part without the alarm coming on. Has anyone else had this same problem? If so, how was it resolved. This machine is 9 months old and has only machined aluminum and plastic nothing heavy duty, but it runs at 3000 to 3500 rpm all day.