The Most Dangerous Second in a PCB Project: A Safe First Power-On
Series navigation: Episode 1: The Roadmap · Episode 7: Reading Arduino Pin-Current Specifications · Episode 15 The problem: Connecting full power immediately can turn one assembly error into several damaged parts. The goal: Make first power-on a sequence of reversible tests with stop conditions. The result: A bring-up checklist from visual inspection to firmware and interfaces. AI-generated illustration of preparation for first power-on. No measurement shown is evidence from a real board. I wanted to plug in USB and see the LED blink After waiting for a new PCB, the natural impulse is to connect everything and run the full program. That single action combines too many unknowns: assembly, polarity, shorts, regulators, clocks, reset, programming, firmware, and external devices. If smoke appears, the evidence has already been destroyed. First power-on should be deliberately boring. The objective is not to demonstrate the whole product. It is to discover the first incorr...