I am running into a problem with my Mega project. It's only working if I have an external power source plugged in, as well as a USB connection. The USB can then be unplugged, leaving a 9V to keep it going. However, the Arduino seems to be unable to run the code if the 9V is ever unplugged, and plugg…

Mega 2560 Rev. 3: Not Working Without Initial USB Connection

Topic		Replies	Views
Mega 2560 has power but no longer appears as a device IDE 1.x	11	4057	May 5, 2021
Driving Mega2560 from external 5V bricks USB port IDE 1.x	48	29556	May 5, 2021
Problem with power supply on arduino mega IDE 1.x	1	497	May 5, 2021
Mega 2560 works just with external power IDE 1.x	5	1469	May 5, 2021
Mega and low voltage, board doesnt power up Troubleshooting	6	1159	May 6, 2021