Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 480)

Section 9A
Operator Interface
9A-13
1. Remove power from the operator panel.
2. Remove the plastic cover from the back of the operator panel. The
cover is attached with three plastic snap pins at the bottom of the
cover. Pull these pins until they snap free of the operator panel.
3. Using a small screw driver, adjust the contrast or sub contrast pot as
shown below. Note these pots are labeled on the printed circuit
board:
Use Contrast Pot found
behind video connector
(Monochrome CRT only)
Use Sub--Contrast Pot found at
far right of video connector
(Color CRT only)
Color CRTs Monochrome CRTs
Important: We do not recommend adjusting any of the “Brightness” pots
located on either CRT types. The brightness controls are preset at the
factory for optimum monitor performance and reliability.
4. Re--attach the plastic cover to the back of the operator panel.
5. Re--establish power to the operator panel.
6. Repeat steps 1 thru 5 until the desired monitor intensity is reached.