If serial console has no output, then there is a good chance of hardware failure. There is one last thing to perhaps test before going for RMA…see if the Jetson shows up when in recovery mode.
If you connect the supplied micro-B USB cable to the Jetson and your desktop host, and put the Jetson in recovery mode (hold down recovery button, either tap power on if system is down or reset if system is already up), your host should see the Jetson on USB. This command would have output, rather than being blank:
lsusb -d 0955:7721
If the Jetson fails to show up even then, go to near the top of this URL and look for “RMA” to see RMA procedure:
If the recovery mode Jetson shows up on USB, then it might be worth further testing.