I have exactly same problem on my yoga 3 pro after getting it back from service for a faulty sdd. The power button does nothing, but has the white led light. As you I go on using it by pressing the recover/boot options button. I do not think this harms the computer in any way, so I just go on living with this problem. I dissasembled the PC to have a look at the connection of the button to the motherboard, but that dit not solve it. (As a curiosity; the Type and Serial number from BIOS also disappeared after service.)

I replaced the components with the connector as recommended by ifixit, and my phone have now worked flawlessly for 2 years after that. (iPhone4) Be warned, not easy, small parts.

Exactly the symptoms! After having changed the docking kit, the phone is as new. Even the microphone improved. However I must say that to put in the replacement parts was ultra fine mecanics.

Same problem. Phone charges from the normal charger. But same cable connected to any USB port on any PC nothing happens. No charging, no driver enabled and no connection to Itunes. An Iphone 3 works fine with same cable. I have cleaned the docking port, and have tried to wriggle it and reinsert it repeatedly, but no reaction on PC. Have looked at the manual for changing the docking port HW, but it seems rather difficult. Anyone had same problem and success changing the docking HW? Would be nice to know before I risk trying this!