It sounds like something is wrong with either the power-block or the cable.
The Chromecast 3rd Gen device uses a standard power-block and micro-usb cable. Try replacing both.
Do NOT plug the Chromecast into a USB port on your TV or gaming system. Often those ports are designed just to read data of thumb drives and are not fully powered. They can't support the power demands of a mini-computer like a Chromecast.
Did you do a hardware reset and the problem still remains??
you can always use the USB direct to a tv USB port too, preferably a blue 3.0 port i guess
i dont know what else to tell you based on all what you tested.
Just wanted to see if you still need help. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours if we won't hear back from you again.
Should that happen, feel free to create a new one if you have more questions or have other concerns in the future.