On the front of the evaporator there is a tilt tray with fingers. On the right hand side is a magnetic. Behind that magnet is a reed switch that tells the machine that 1) harvest is complete. And 2) that the bin is full because the weight of the ice kept it in a tilt position. Now the common reason the tilt plate doesn't come back all the way when the ice melts is machine cleanliness. And the tray binds to the pivots from mineral build up.
Start by using some Manitowoc ice machine cleaner in a extended mode as per the Service manual.
Now the key pad is another question. Does the bin full light in the bottom corner of the indicator light when the bin is full? Do you have a service light? If not, go to page 59 in the manual I linked above. The control board is in the box underneath the ice bin to the left of the condenser.
Also the operation manual is here;
And the parts manual here