The Marlin firmware has a default baud rate in its program.
For my printer it is 115200. I have run the printer on the highest pronterface setting.
Power supply ------ I can't run my printer without the USB plugged in. If you figure out how to fix, let me know!!!!! I have LCD.
My cooling fan is not working yet. I have it plugged into D9 on the ramps board. I was told it is controlled at pronterface.
I sent you private message about instructions.