Bad luck this week. Yesterday it was a defective pi, today it was a short circuit in a power converter! It damaged a PCB (whose trace acted like a fuse), but I was able to repair that
Normally it takes like 30 minutes to build one unit, but these two have taken well over 2 hours on account of all the troubleshooting and re-work that had to be done.
I don't expect bad components, so the first thing I look for are mistakes that I made. Maybe those days are behind me and I should check parts now?