hmm ok… it sounds like a cold solder joint. Basically the wire we use is coated and the lead free soldering process used to bond the wire to the inductor input on the chip must be hot enough to burn the coating off the wire and make a solid electronic connection, but sometimes the solder process is too fast or the heat transfer from source to target is not efficient and you end up with a cold solder joint which works but the wire is just sitting in a pocket of solder and not mechanically bonded… so it’s literally a loose connection that will work sometimes and if you jostle or jolt it, can stop working… it’s very hard to test for these situations because often times we test and it works… chips that fail to work we consider failed and remove, but if testing is passed we ship it… and maybe that connection works fine for a while but after normal use it can become intermittent.
We are working on ways to test for this, possibly by x-ray examination, but we need the testing method to remain cheap enough that the cost to produce doesn’t skyrocket.
For now let’s consider the NExT defective. Reply to your order confirmation email with this forum link and we will ship you out a replacement. Sorry this happened 