I have a project where I have to buy a lot of Dues (over 150 so far). I'm seeing this issue with about one out of every 25: They work fine when connected via USB to a computer. But they do not work when 12v is applied to the Due 2.1mm power connector, or when 12v is applied to the Vin pin.
It is not an issue with the power supply because I've tried several, between 5v and 12v. I also see this is a common problem with other Arduino models, but I have never found anyone with a definitive answer.
BTW, for me this is a problem out of the box, it's not a situation where the Arduino was working, then later not.
Could this be a voltage regulator problem, or something reparable?
Whoa! That's a substantial amount of computing power!
"Real" Dues, or clones? They tend to have different power circuitry. There have been assorted reports leading me to believe that SOME clones might have faulty regulator circuitry or chips (although so far, that's shown up mostly in AVR-based boards.)
Have you traced out (voltmeter or scope) where the power is failing? 12V in, diode, 5V regulator, auto-switch power selector, 3V regulator, ... ?
Ha ha, it's not 150 Dues in one project - I design kits.
They are Chinese clones. I assumed it might have something to do with a faulty regulator on clones. I have a multimeter, so I'll try figuring out where the power is failing.