There should be two cables coming from the Roku device. One is an HDMI cable (this is the audio and video signal cable) and the other is a USB power cable.
There is a micro USB connection on one end that plugs into the device, and the other end is a USB-A connection that you can either connect directly to your TV (if applicable) for power, or you can connect it to the power adapter and plug directly into a wall outlet.
How are you currently powering your Roku device?
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