what might happened to my BBB?

When I tried my HDMI cable, plugged it in. and also with a 5V2A power supply, it works.
But when I plugged in a apple keyboard through the USB host, the power just turned off.
And now it just gives a response of a blink of power led when I plug in the power.
What can I do? only RMA?

I would suggest an RMA to see what happened.