The obvious clue is:
I opened up my D8B to clean the faders
It's hard to say without knowing EXACTLY what you did when you opened it up to clean the faders.
Most likely, some connector got unseated. Open it up again and check all the connectors going to and from the fader boards. And check all the others as well. You might have accidentally unseated something nearby.
And also make sure there isn't and loose foreign objects sitting on any of the boards....like a screw or something.