digging around I've found an Arduino Mega just laying there, so I tried to hook it up to my 3D printer (been brainless for a while). Since the connections should be good but there's something not working as intended, I've checked the board.
While powered through USB, the onboard LED lights up and the 5v pin outputs circa 4.8-4.9V.
When powered through a battery pack (4x1.5V) it outputs only around 1.7V, and no light from the onboard LED.
Should I check in another different way, or is this enough to say the regulator is faulty?
Thanks in advance!