This is an odd one. I have three large 7-segment displays connected up to an Arduino Uno board. I tried using an Arduino Uno Wifi Rev2 board to control the digits, but one of the segments (the upper-left vertical segment, labeled “F” on the datasheet) is not lighting up consistently.
After some exploration it turns out that if that segment and the center segment (labeled “G” in the datasheet) are lit up, ONLY the center segment is lit. So the digits 4, 5, 6, 8, and 9 are not displayed correctly.
But when I moved back to using an Arduino Uno board (without wifi), the segments light up okay.
I have tested two Arduino Wifi boards with this setup (both boards up-to-date with the latest firmware), and both are displaying this issue. Any idea what might be going on here?