Four real, worked diagnostic scenarios — a board that fails only in the field, a power rail that corrupts a nearby ADC, an FPGA design that passes simulation but fails on real hardware, and an intermittent I2C bus lockup — each solved with the symptoms-diagnosis-testing-resolution discipline Module 15's tools and methodology make possible.
Re-flashing firmware and hoping, or swapping a board and moving on the moment it happens to boot, is a guess dressed up as a repair — and a guess that works is indistinguishable from luck until the same fault comes back. This module works through four real diagnostic scenarios where the visible symptom has at least two plausible causes that look identical from the outside: a digital board that passes every bench test but fails intermittently in the field, and a power rail that reads perfectly fine on a multimeter while a nearby ADC reads noisy.
It also works through an FPGA design that passes a full simulation regression but fails only on real silicon, and an I2C bus that locks up unpredictably with no obvious pattern. Each scenario follows the same Symptoms → Diagnosis → Testing Steps → Resolution structure and leans directly on Module 15's oscilloscope technique, logic and protocol analyzer use, and JTAG-based debug — the actual tools this program teaches you to work a real diagnostic problem with, not just recognize one after the fact.