I am having literally the same problem. I disassembled to change the outer shell with speakers and now it will not charge and no LED light indicating that it is charging. Do I have to have that front face sensor cable attached to see if reseating the cable works? I didn’t work anywhere close to carpet to short out the motherboard but I’m baffled at this point.
I followed these directions which were amazing and very helpful, but after reassembling the headset it won’t turn on. Any ideas on why? I rechecked the power flex & it’s in there.