power up problem

When i plug in the board the led turn on, everythings seems to work fine, but after 5-7 seconds the systems shut down. doesn’t seems a charger problem. Any suggestions?

Often it is just a video issue. How do you know the board truly powers down? Are you able to watch your router to see if DHCP has gone out? Can you ping before the power down, and show ping stops at that moment? Does the LED go off? Do you have a serial console?

first: thank you for the response. second: sorry for my late reply.
The led go off and the fan stops so I assume the board power down. yes i have a RS232 cable to control the board for debug, and prior this problem i was able to use minicom to connect to the board.

The LED should be a valid indicator. Make sure the issue still exists with nothing plugged in to USB or HDMI. If this does not indicate a peripheral causing the issue, then possibilities are fairly limited and probably failure.

If there isn’t something unusual about the environment (e.g., 99% humidity or high heat), then it probably should not do this. If you see a message on serial console right at or just before shutdown, then this could offer a clue. Given that your power source is valid and that this is repeatable though I am thinking hardware failure and time for RMA.

One thing you could still do as a test (which I doubt will change needing to RMA) is to see if it stays up when you put it in recovery mode. Hold down the recovery button, tap power on, and see if the micro-B USB cable shows up on the host with “lsusb -d 0955:7140” (type that in to the command line, but don’t hit the enter key until right after the TK1 powers on). Much less of the system is running in recovery mode, or at least clocks are not maxed out. If it shuts down under recovery mode with only the micro-B USB cable connected, then it is a virtual guarantee that the hardware is bad.

If you want to RMA there is a summary near the top of this: