Scotsman stand ice machine unit fills up 1/2 way with ice.

My first question is, when the ice maker is half full, is it still running or does it shut off when half full? If it shuts off then I would suspect the bin thermostat. If it is still running and making ice then you need to look for the reason it cannot fill up. Many possibilities, seeping water valve, dirty condenser, bleeding solenoid valve, low on refrigerant, drain water not draining quickly enough.