Cause 1: You are using a conversion connector

If the connection is made using a conversion connector such as Display Port to HDMI, the screen may not be displayed.

This is because Display Port++ is not supported on Jetson. Try to connect the monitor without using a conversion connector.

Cause 2: Power save mode

After a certain period of time has passed without any operation, the power save mode will be entered. In that state, the screen is not displayed.

In this case, typing something on the keyboard will resume the screen display.

Cause 3: There is an inconsistency between the bootloader and the image in the micro SD card

NVIDIA Forum: Boot failed with 'Find Partition via PT Failed'

https://forums.developer.nvidia.com/t/boot-failed-with-find-partition-via-pt-failed/172663/5

As mentioned in the above forum, if there is any mismatch between the bootloader on the QSPI NOR Flash on the Jetson Nano module and the image on the micro SD card, the image will not be displayed on the screen without booting. There is likely to be.

Based on the above forum, use the SDK Manager to rewrite the latest JetPack to the micro SD card, then start it and check if the image is output on the screen.

Also, if you are using JetPack 4.5 or later, the same phenomenon may occur if you rewrite the image with Etcher.

Please note that a Linux PC with SDK Manager installed is required to restore.

The PC requirements for running the SDK Manager are summarized below.

https://docs.nvidia.com/sdk-manager/system-requirements/index.html