Recalibrating the touchscreen on your Retro C is really easy to do and can be completed in less than 5 minutes. If you find that when you touch screen the cursor is off the steps outlined here can help tremendously.
There are a few ways to diagnose the issue. Get a known working good cable and run it into the VC1 for the movement. Note: In order to know which vc1 it runs into the check screen will indicate it. The vc1’s are labeled V(Number) IE V12. They are the same in the electrical box.