Surface Pro 3 will not turn on, doesn't appear to charge
I have a surface pro 3 that one day decided to not turn on. I charged it for a while, nothing on the screen, no sound. I tried holding the power button in for 15-20 seconds, tried the +volume and power button together, nothing. I ordered a replacement charger and battery. Tried the new charger, no change. I bit the bullet and took the display off (and did crack it, grrrr!). I replaced the battery, still will not power on or show any indication of life. Any idea what I could check, or what it might be?
I get .85V at the battery connection with the charger plugged in. The battery is completely dead.
Update - I replaced the motherboard today with a supposed good motherboard. Still no reaction when pressing the power button or +volume and powerbutton together.
Could a faulty powerbutton cause this? Anyone know what I could short on the motherboard to simulate the power button being pressed?