External Axes Calibration

DPatel Canada
Hello All,
Greetings of the day!
 I am Currently working On Mig/Spot welding weld cell.  For mig welding i am working with two robots and three external axes.  Two MTD 250 fixures and 1 MID 1000 turn table. I am trying to find the witness marks on the external axes because the turntable is showing unusual values on the flexpendent. I want to rotate it up to 180 degrees max (For all of the external axes) so that i do not damage the cables beneath it.

What should i do?