Hello, I have restored several years an old 8753B with a dead display. After a long search, I have found a display from another defective unit and installed it. The base intensity level after switching on is 45%. In this setting the display is extremly bright and out of focus. I have to reduce the intensity level immediately to 20% to protect the CRT. After that the focus is much better than before. At 20% the brightness is normal, at 16% the display is completely dark. Which opportunities exist to reduce the initial setting of brightness? What exactly is the effect of the intensity cut-off level control (A1R131) in the 1349A/D display?