Roland RD-700nx display screen is fading badly; why?
When you say fading, are you referring to the backlight or the contrast of the text on the screen?
Assuming you’re referring to the backlight, what first comes to mind is that this 20 year old display’s EL (Electroluminescence) backlight could be on its way out. I have a Yamaha CS2X suffering from the same problem.
Looking at the service manual for this unit, the display is a Kyocera F-51320GNY-LY-AA.
I’m not sure how easy it will be to still find a replacement screen. Perhaps it might be worth looking into replacing the EL backlight only. I personally don’t have experience with this but maybe someone else on this forum does?