Generic I²C 128×64 OLED Displays: Beware Swapped VCC and GND

A batch of 1.3 inch white I²C OLED displays arrived from halfway around the planet, so I figured I could run a quick acceptance test by popping them into the socket on the crystal tester proto board:

White 1.3 inch OLED on crystal tester
White 1.3 inch OLED on crystal tester

The first one flat-out didn’t work, as in not at all. The original display continued to work fine, so I compared the old & new displays:

OLED Modules - pinout difference
OLED Modules – pinout difference

Yup, swapped VCC and GND pins. I should be used to that by now.

I rewired the socket, tried the new displays, undid the change, popped the original display in place, and all is right with the world. Somewhat to my surprise, all five new displays worked, including the one I’d insulted with reversed power.