I'm pretty inexperienced at electronics (but learning!) and recently had some PCBs manufactured for a project I'm working on. I had 40 PCBs made (PCB Assembly done by the manufacturer) and received them earlier today.
While my PCB does several things, I'm only concerned about one specific part here; the power system. I power this system with a 3.0-3.6V battery (Temperature/Current-dependent), and it is supposed to boost this to a steady 3.6V to power a Particle Electron with (using two wires with a JST-PH2 plug, connected at W1/W2).
W1/W2: JST-PH2 w/ wires (to be inserted directly into a Particle Electron)
I based my design off the TPS61099x datasheet and quite religiously followed everything in it (e.g. schematic, recommended parts). I thought it would work.
For 10 of my PCBs, everything works fine. The Particle Electron is nicely powered up and everything runs as it should.
For the remaining 30 PCBs, as soon as I connect my Particle Electron (i.e. current is drawn) the output voltage immediately dips to ~0.9V.
I'm at a complete loss as how this happened. These PCBs were assembled by the manufacturer so I assume they should be identical/free of assembly errors. I also can't observe any visual differences that would hint at a wrong part, or part being placed incorrectly. The batteries can handle up to 2A, which is way more than a Particle Electron would possibly draw (max. 800mA). What could be a possible reason only some of my PCBs work? What should I look into first? I simply have no idea how to approach this issue and where to start with fixing it.
I can share my information if needed.