Hi everyone! I recently started to build a RepRap Prusa i3 from the scratch.

Hi everyone! I recently started to build a RepRap Prusa i3 from the scratch. The boards used are the SainSmart MEGA 2560 and the Sainsmart RAMPS. But there’s a problem that has been keeping me from finishing the printer. When connected to the computer with the RAMPS attached, not even with the PSU turned on or plugged, that green on the “Arduino” chip starts heating real quick. I checked the voltage on the PSU and it’s exactly 12 V. What should I do? Should I replace the MEGA, buy a voltage regulator? Halp pls.

If the Atmel chip starts heating up real quick, I’d get SainSmart to replace the board. You didn’t accidentally hook power up backwards at any point did you? Generally what I start doing at that point is disconnecting and double checking wiring.

If you disconnect the RAMPS, and hook up the MEGA to the computer simply by itself…is it fine?

I never hooked up power backwards. The thing is that when the MEGA is connected to the computer it works nice, but when I hook up the RAMPS it starts getting hot. Thanks for your help

Yep – time to disconnect everything, and then start reconnecting one piece at a time, start with your thermistor. Check that your RAMPS+MEGA respond each time you add something new. Don’t let the Atmel chip on the MEGA get too hot. I have a feeling it might be your endstops.

You got good feelings, I disconected the Endstops and I can now connect everything to the computer and use Pronterface. But It doesn’t ends here, i’m really new to this, could you help me with what I believe is the hardest part (calibration, setup, etc…)