We just got done isntalling a 1993 3016...serial number puts the machine right around 2000th one made in that year. It has a CNC88 control box and 88HS internals. They must have had a bunch of left over CNC88 control/monitor boxes when they started making the jump to 88-HS . We also have a 1993 model and the serial number puts it around 7000nth one made...it has a CNC88-HS control box. I wonder what was the last serial number to get a hs (-4) control in a 88 box...maybe a collector item for Scott_Bob?