Reminder why important to check D flip-flop polarity before you solder!

This is an important reminder as per today, 22 December 2025. Please double-check the polarity of the D flip-flop before soldering it onto the board.

Why it matters: Soldering it with the wrong polarity can damage other parts of the board. It could burn out the voltage regulator, cause the electrolytic capacitors to fail, or worst of all, end up fry the main Black Pill microcontroller.

Where to look: The correct placement is shown on Page 51 of the guide. Based on the position marking on the PCB, the chip should be placed at the bottom of its footprint.

Common mistake: Do not place the position marking up near the 1 kΩ SMD resistor. That is the wrong spot and polarity.

Final reference: Always compare your work with the picture of the fully assembled board on Page 5 to make sure everything is in the right place.

Taking one minute to check this now can save hours of troubleshooting and repairing damage later.

At the end of the day, there’s no point in blaming components or the PCB. Sometimes the culprit has been holding the soldering iron all along.

Better safe than sorry is the best practice here.