You are missing the fact that the SATA connector on the board is not connected to 12V. See also this thread that discusses it: https://www.udoo.org/forum/threads/udoo-x86-dont-recognizes-sata-ports.7547/
Oh right, I see, thank you so much. But if I just rig up a sata power connector to CN12 which has 12V, GND, GND, 5V even in that order it should work, right?
It could work if your drive does not use too much current. You better hook up the 12V for SATA directly from an external 12V source.
What if I just use a higher current power supply? say 5A instead of 3A. Could I break the Udoo by sending too much current through the 12V rail?
Yes, you can take that risk and destroy your board if it goes wrong. You better make a power wire for Udoo and HDD like someone did and explained earlier in this thread. Costs to make are nothing compared to a destroyed Udoo board. Udoo did not connect that SATA 12V connector for a reason (overload the 12V rail)
On page 17 of the manual I find written that the maximum consumption in stress test is 1008mA 1020mA 906mA so we should be able to associate a hdd3.5 So I was thinking, if I took the 12v from the fan connector? It's possible?
No. 1) It is not always on, and 2) You don't want to burn that tiny MOSFET (save pennies and risk hundreds)
I have a Seagate Barracuda 3TB 3,5 inches, plugged by USB3 rack (https://www.amazon.it/gp/product/B0725Z3BZV) but i cannot see it in windows 10. It was seen as "EXTERNAL USB3.0 SCSI DISK DEVICE" in device list.
3139U3 needs a standalone/separate 12V external DC power feed. Per datasheet http://www.orico.cc/goods.php?id=6478 under Win 10, USAP protocol is supported. Not sure Win 10 needs to fetch the driver for that or not. ccs_hello
