Hello - finished printing my Otto (Starter ) and assembled servos and electronics. Mine uses the USB-9V battery. The JST plug had red and black wires reversed. Swapped the pins and now I have the same problem powering the Otto. When connected to the USB programming port everything works fine. When I disconnect the USB cable and turn the internal power on - the nano board continues to loop and beep. Measured the +5 volts on the nano board and when the sounder beeps the voltage drops to 4 volts. I believe the 5v regulator on the board is over loaded - too much current is being pulled by the servos. If I disconnect all of the servos and power on with 9v battery there is only 1 beep has the board boots up. The AMS1117-5.0 5v regulator measures 6v output. This part may be faulty or there is a cold solder joint.
When using the USB programming port it provides 5v @ 500 mA (USB2.0 standard) and bypasses the AMS1117-5.0 voltage regulator.
Please advise next steps. Thank you