The TDS 500, 600, 700 series are CRT with the shutter system. Pink to one side as mentioned could be only an artifact of camera shutter speed. The normal failure of the shutter usually comes from a physical shock to the front of the display and it usually takes the form of a discolored blob in one area. CCFL is used only in the newer series like TDS2000, TDS3000. Also be aware, the colors can be edited on the older 600 / 700 series. I have the trace colors on my TDS644B edited to match the new TEK scope colors, 1=Yellow, 2=Blue, 3=Magenta, 4=Green.