Can anyone help identify the component that is missing from this circuit board? The board is the main controller board for a music keyboard. The keyboard is meant to be able to be powered over USB but due to the missing component (presumably) this doesn't work. The keyboard can also be powered via a separate DC jack, which takes power from a 9V 200mA DC adapter (this does work).
Below is an image of part of the mainboard, the USB connector is centre-bottom. Just above that is the missing component, marked L19. The bottom pad of this is connected to the +5V pin on the USB connector. To the right of the USB connector is the DC jack.
Next to the missing L19 are two components labelled L20 and L21 - I presume these are the same as the missing component, but I don't know what they are. A larger image of these is below.
I have contacted the manufacturer but they won't tell me what the component is, so I'm hoping someone here might be able to help me.