Today I played around with one of my 16*2 LCD shields. All of a sudden it switched all pixels on. At least it looked like that. I figured that if I look from the side then the display is still correct. So seems there is something going of with the contrast / brightness. Switched to my backup shield --> same behavior. Switched the Arduino board --> same behavior. I never tried the backup shield before, so maybe it already had an issue before. But the primary shield exhibits the same behavior now.
After shaking the shield a lot it recovered. Any hints what could be broken or where I should look for a cold solder joint?
Cheers, Udo