Here's my problem to add to the pile. My SP4 stopped charging off the official power supply. I purchased another MS power supply and still get the blinking light and no charging. I have verified that both power supplies are good. The interesting thing is, I have a Ravpower, Model RP-PB14, 23000mAh /85Wh battery pack with charging cable and it charges my SP4 perfectly fine. I've tried every power combo I can think of short of a full factory reset as well as removing and reinstalling the power drivers with no change. I even contacted MS tech support and after they updated the drivers the same as I did, there was no change and tech support gave up on me. Any ideas would be appreciated.