MCU overheat and LD4 blinking

[Winston Smith]

I’m a rookie on STM32, this afternoon I experienced overcurrent on my board and expect to get some help to make sure my board can still function fully.

My board is NUCLEO-G431RB. I connected my board with both STLink and 4 AA batteries, with JP5 jumper cap on 5V_STLK. Then the LD4 (overcurrent) started to blink and the MCU became extremely hot. 

After that, I tried to connect the board only with 4 AA batteries (JP5 jumper cap on 5V_VIN), though the circuit (serval LEDs and resistors) powered by the board still worked and LD4 did not blinking, the MCU temperature was very high (approximately 80-90℃).

 

Appreciate anyone who can guide me on checking my board’s condition!



I’ve tested the resistance between serval pins when the board was not powered:
3v3-gnd, gnd-3v3: gradually increase to 525Ω.

5v-gnd, gnd-5v: 871Ω-857Ω.

Vin-gnd: Over Limit.
gnd-Vin: more than 16MΩ, decreasing gradually. Sometimes Over Limit.

I’ve tested the resistance between serval pins when the boaerd was powered through ST-Link (JP5 5V-STLK):
3v3-gnd: 0Ω.
5v-gnd: from 7kΩ to 0Ω.
Vin-gnd: Over Limit:
gnd-Vin: more than 16MΩ, decreasing gradually. Sometimes Over Limit.

[rich.g.williams]

That’s not good news unfortunately.

Booting Nucleo Boards at 4 Volts

[Winston Smith]

Thank you for providing your notes. 

Then the heat might because of shorting pins? 
I’ve done a few tests, the board can still download file from computer, and GPIO output seems normal.

Considering the heat up situation, can we still treat the board as healthy? If not I have to buy a new one.😭

[rich.g.williams]

OK suggest you disconnect everything from the PCB then power it up holding the reset button down.  This makes almost all port pins analogue or input.  If the MCU is still getting hot you have a problem.

You could also actually measure the current drawn by the PCB.  While its in reset the current should be low, also put the STLINK MCU into reset using JP3,  the current should be below 100mA (check the data) more like 50mA but the MCU should not be hot held in reset.

“I’ve done a few tests, the board can still download file from computer, and GPIO output seems normal.” 

Does the MCU load and run a program (led flashing for example). If it runs a program that’s a good sign and its worth looking for shorted pins etc.

Also wait until Monday some of the ST Moderators/Employees may have some suggestions.