Barrel connector and 12v = Smoked Atmega 2560

Hi, I plugged a 12v DC bench supply into my Atmega2560 with Ramps board. No usb plugged in. Powered through barrel connector. As soon as I turned on the bench power supply - my board smoked. I verified that it as dial to 12v. Not sure if it ruined my ramps board.

Not sure what the problem is - supposed to be able to take 12v. Is it possible that the barrel connector has the wrong polarity or it is simply that I should send 12v to the ATmega and instead power the ramps board?


Most Arduinos have a diode on the jack, therefore reverse power would not be the cause.

More than likely, the power supply was set too high or had a fault at power up.

We would need to see a good image of the wiring to make a better comment.

Could You take a picture of the exact place where this happened?
Add a description telling what that desk space generally is used for?

Unless that is what smoked...

Well, that would mean something down the road shorted :sob:

OK, here I go again. :roll_eyes:

I admittedly do not know what the usual power configuration for a RAMPS board is, but the on-board regulator on a Mega 2560, as on the UNO, Leonardo etc., is simply not suitable for powering any "serious" project, so supplying power to "Vin" or the "barrel jack" is a terrible idea under any such circumstances!

The logic requires regulated 5 V. Supply it with regulated 5 V. Either to the "5V" pin (proper way) or the USB port (but then you have to connect the 5 V separately to the other devices, not from the "5V" pin). Just be careful not to supply to the "5V" pin when you have the USB connected to a PC.

Boy am I lucky, was going to send you the barrel jacks that I don’t use anymore. :nerd_face:

thanks all. Nothing was really wired to it yet. Just the ramps board plugged into the mega. Must have been a surge of voltage from the benchtop power supply. It was set to 12.00 V but .... Points all taken. Won't do that again :slightly_smiling_face:

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.