Hi. Im haveing this issue: I have my 3d printer (prusa i3) with a reprapdicont lcd controller. It is independent from my PC computer (or it was). I print from the SD card in the controller. All worked ok, till I decided an upgrade: to add a rapberry pi3 so I has online capabilities to monitor the prints.
So I added the raspberry pi3, also at the same time, I modified the cable lenght of the rerapdiscount controller, they are longer now.
when I tried to test everything, I found that if I dont connect the USB cable to the raspberry card, the lcd does not power on. If I connect the USB, everything works very nice.
I have been searching through the forum and I found posts about this but all of them are somehow too technical for my level of electronic knowledge (sorry for the ignorance).
I checked if diode D1 was present in the ramps, and yes, it is there. I tested it with a multimeter and the diode seems to be ok.
So, acording to what I have read, the failure could be located in the voltage regulator of the arduino? Wich takes me to 2 questions: why everything was working ok before bringing into the game the raspberry? I mean: the lcd was wrking ok without haveing a usb cable conected. Question 2: how can I solve it? Changeing the voltage regulator would be a somehow difficult solution for my really low electronics skills. I read that I can power the arduino through the barrel. Can I do that? I should disconect/cut the D1 diode in the ramps right? also, the power into the arduino should be a 12V power supply? + in the center of the barrel?