On my single sided pcb, I ended up with my SOT-23 mosfet gate and source connections swapped. Having checked the footprint is correct, by replacing the SOT-23 n-channel mosfet foorprint (Ao3404A) with some known SOT-23 npn transistors – MMBTA42 and BCX70 – where the base and emitters ended up swapped. So my only conclusion, is …
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