There comes a time in each of our lives when we have to say to ourselves "Wow, you really are truly, incredibly stupid, aren't you?" Most people don't have occasion to say this to themselves very often, but I am not like most people. I get to do it far more often than most.
My main keyboard, my Yamaha, has a single large LCD display which tells me everything. What patch, what settings, everything. The display was fried, a beautiful purplish-white with just a hint of the text and icons I was supposed to be able to read. Hey, it's seven years old, and I'm happy to say that it's been used quite a bit during that time, so it's not really surprising. It's just not exactly good news. Fixing the keyboard, including replacing the display, would cost nearly as much as getting a brand new one, so it was declared a total loss by my own august authority.
John, guitarist, band leader, and someone who is much smarter than me, did some research and found that fried displays are not uncommon in this whole line of Yamaha keyboards. But out of dozens of reported cases, only one had symptoms which really fit mine. Someone else smarter than me, on one of those Internet technical help boards, asked "Have you tried adjusting the Contrast?"
No facepalm, not here. Directly to slapping myself in the face, hard (mentally). It cannot be that simple. How do you adjust the Contrast?
"It's one of the knobs on the back."
It is.