I have 2 authentic DUEs that I recently bought from the ardiono.cc store. Both will power up with a USB cable connected. Neither will power up with 12VDC connected to the power jack. The 12V power supply I'm using works with an UNO and it's current capacity is 18A. I can measure 12V at the Vin pin so I know it's at least working through the input filter and protection diode.
Has anybody had this issue with an authentic DUE? If so what's the solution?
I have no recollection of a similar topic for this issue with the power jack. IMO the best you can do is asking a refund to your arduino board reseller.
I have the same problem with my arduino dues. I ordered one due several weeks ago and that one works fine with 12V external Power supply. The dues that I ordered last week do not accept the 12V external power. I recoqnised that on the newer boards one electronic component near the 12V-plug is different to the older board. As described by r-wilder, the Vin-PIN gets 12V but all LEDs stay dark.
That suggests, that maybe all newer boards have this bug.
Dues were ordered at Conrad.
EDIT: At the 5V-PIN there are only 1.24 V
and on the 3.3 V-PIN only 0.45 V