And so what did I2CexpDiag show?
Did you try adjusting the pot?
That pot will require many turns to make a difference.
At one end you will see no pixels, at the other, all pixels will always be on.
Somewhere in between the pixels will work as expected.
That is an odd way to solder the backpack. The pin orientation isn't changed, but usually the backpack is soldered so the
backpack doesn't stick up above the LCD PCB.
On that backpack (and I have few them), I replace the pot and relocate it.
- I don't like multi turn pots for LCDs
- I want the pot on the other side of the backpack PCB
Moving the pot allows it to be accessed when the backpack is flipped/rotated around so the chips on the backpack face the LCD module
and the backpack won't stick out beyond the LCD module.
--- bill