RAK3172 Breakout Board Suddenly Disconnects

Hello,

I have a RAK3172 that I used to connect to the laptop over USB-TTL. Previously, when I open WisTool Box, the board would be detected and communicable from the first time and the times following. It would work fine with my code, sending and receiving to multiple nodes for days.

Now, The same RAK3172 will not operate or become identified on WisTool Box unless it is externally powered. I checked the USB-TTL and it outputs 3.3V no problem. I tried different adaptors and the RAK3172 acts the same to all. I switched to using a power supply with a stable 3.3V to power up the RAK3172 (with a common GND between the USB-TTL, the RAK board, and the power supply). With the external power supply, the RAK3172 will ONLY SOMETIMES be detected on WisToolBox, and other times it will just drop and not be identified again until I switch off and on the power supply.

I bought new RAK3172 board and it does the same.

Even when I can successfully use the RAK3172 (externally powered) for my code and it sends and receives to the node, it will only last 5 mins before I lose it again and I will need to restart the RAK3172 and my project.

Your assistance is greatly appreciated as it is a business sensitive matter.

Did you try different cable from the USB-TTL to the breakout board?

Could be a bad contact in the cable.

Check the voltage directly on the RAK3172 if it receives 3.3V.

Do you use RUI3 AT command firmware or a custom firmware?
If you use a custom firmware, do you have a lot of debug output over the UART2?

Did you try a serial terminal application instead of WisToolBox?