Jetson Nano still supplying power after sudo shutdown command

I’m trying to use a Jetson Nano to power two relays using the 3.3V output pins. The system was functioning a couple of months ago but recent there have been issues that have shown up. The main issue was that when I shutdown the Jetson Nano using the “sudo shutdown now” command the Jetson will shut down (light turns off and I’m unable to connect) but still provide power to the relays. While trying to debug, I discovered that the 3.3V pins are actually outputting 5V. Testing showed that once the Jetson is powered, both pins output 5V of power and continue to do so until the power is pulled, even if the “sudo shutdown now” command is used. What could have caused the pins to switch output power?

The Jetson is powered using a power regulator that inputs into the two 5V pins.

Could you show us a diagram or schematic? Which pins are used to control the replays? It’s hard to find the connection from above
description.

I am using pins 2 and 4 to power the jetson by supplying 5V of power to both pins from a power regulator. Pins 1 and 17 (the two 3.3V pins) are then used to power two relays once the Jetson has been turned on. When checking pins 1 and 17 with a multimeter, both pins are supplying 5V of power instead of the expected 3.3Vs. On another Jetson Nano that I have, pins 1 and 17 both read 3.3V when checked with a multimeter.

To find out where the 5V on 3.3V pins is from, please remove pin 1 and pin 17 connections to the relays, then check the voltage on pin 1 and pin 17.

  • If pin 1 and pin 17 is 3.3V, there is a leakage from relay.
  • If pin 1 and pin 17 is still 5V, the 3.3V regulator U9 on carrier board may be broken.

Ok. I checked if the voltage was the same without the regulators plugged into the Nano and the reading was the same. I guess that means that the on board regulator is broken. Are you allow/able to provide me with the part number for that regulator? I would like to look at potentially replacing it.

U9 is MP2384. Suggest checking VDD_3V3_SYS related circuits in Jetson Nano Developer Kit Carrier Board Design Files (P3449 B01).