If you experience that the ON LED (green light) on the board does not turn on when your board is connected and you are concerned about it, read the following. Depending on the board you have this can be a normal behavior. It could also mean that the board is not receiving power and it is faulty or got damaged.
If you have a Portenta H7 board, this behavior is completely normal. The LED does not turn on unless we upload a sketch to instruct that. The RGB LED only blinks once when first plugged in or reset.
If you're using a Diecimila or older USB board (e.g. NG), make sure that the jumper (little plastic piece near the USB plug) is on the correct pins. If you're powering the board with an external power supply (plugged into the power plug), the jumper should be on the two pins closest to the power plug. If you're powering the board through the USB, the jumper should be on the two pins closest to the USB plug. This picture shows the arrangement for powering the board from the USB port.
If after reading the above advice you experience that your board's ON LED does not turn on when the board is properly powered contact our Technical Support Team.