I have an Arduino UNO ch430 clone. It works with USB power supply, I can upload a Sketch and it works just fine. With external power supply, doesn't work. What do I mean? No LED lights up, high pins output ~ 0V. I'm using that barrel jack plug with 9V (6 x 1,5V batteries). Input voltage is measured OK. The AMS1117 regulator has Vin pin = Vout pin; i mean it gets no input Voltage. On the other hand, the M7F rectifier diode that comes between the jack and the regulator takes all voltage. I don't understan why, given that the anode is at higher voltage than the cathode (+9V). It shouldn't block current flow. I tried jumping the rectifier and getting the jack +pin directly to the Vin at the regulator: current starts to flow, but apparently so much that the ams1117 heats a lot and really fast. Well i don't know why it suddendly gets so much current, I have absolutely nothing pluged to the board and I couldn't find any stain or damaged spot on it.
I can't figure out what is happening. I hope you can help me, and thanks in advance.
This is an exact (i'm pretty sure) schematic of my board. Link