NUCLEO-H753ZI – ST-LINK Target Not Detected, U2 Heating

[saigsk10]

 NUCLEO-H753ZI Board Recovery
 

Case Description:

 

STMicroelectronics ST-LINK GDB server. Version 7.11.0

Copyright (c) 2025, STMicroelectronics. All rights reserved.

 

Starting server with the following options:

Persistent Mode : Disabled

Logging Level : 1

Listen Port Number : 61234

Status Refresh Delay : 15s

Verbose Mode : Disabled

SWD Debug : Enabled

InitWhile : Enabled

 

Target no device found

 

Error in initializing ST-LINK device.

Reason: No device found on target.

 

 

Board: NUCLEO-H753ZI

Board part number: MB1364-H753ZI-E01

MCU: STM32H753ZIT6 / STM32H753ZI

Affected quantity: 3 boards

 

 

I have three NUCLEO-H753ZI boards, model MB1364-H753ZI-E01, with the same hardware issue. On all three boards, U2 (5V ST-LINK protection IC) becomes significantly hot when the board is powered through the USB connector, and LD6 (ST-LINK USB overcurrent indicator) blinks red. "Error in initializing ST-LINK device."

I checked the board and found that 5V is present at the input of U2, but the output toward the ST-LINK section is approximately 0V. Only U2 is heating; no other IC is noticeably heating. I replaced U2 with a new IC, but the same problem remains and the replacement U2 also heats up.

Please advise how to diagnose the downstream circuit and identify the root cause. I would also like to know whether these three boards can be repaired/recovered and which components or power paths should be checked.

 

[AScha.3]

Hi,

>I have three NUCLEO-H753ZI boards, model MB1364-H753ZI-E01, with the same hardware issue. 

1. all boards been new and working fine ?
2. > hot when the board is powered through the USB connector< which one , debug or user port ?
3. what you did exactly, when working state → no more working “happened” ?
4. what was connected to the board and what is/was power source? + jumper settings changed ?
5. why 3 boards with same problem or defect ? One accident can happen, second time same is very suspicious, but third time doing same error is … psychological problem: intentional damaging something ?

[saigsk10]

Hi, all three NUCLEO-H753ZI boards (MB1364-H753ZI-E01) were working initially, but the issue occurred on each board separately, with a gap of approximately one to two months between the incidents. All three boards now show similar symptoms when powered through the CN1 ST-LINK USB connector using the 5 V supply from the PC: the U2 IC heats up, LED6 blinks red, and the ST-LINK debugger cannot connect to the target MCU. Out of the three boards, two were used for UART testing and TMC2209 motor driver experiments, where I used the same hardware connections that had worked properly during earlier testing. The third board developed the same issue during different work, not during the TMC2209 UART experiments. The JP2 jumper was set with pins 1 and 2 connected for ST-LINK selection. I also replaced the U2 IC on one of the affected boards, but the problem remained. The three boards did not fail at the same time; the issues occurred separately over a period of one to two months. And I cannot yet confirm the exact root cause. Since the same symptoms appeared on all three boards, I understand the concern and want to investigate the USB power path, ST-LINK circuitry, UART connections, and other relevant components to determine what caused the failures. At this stage, I cannot confirm the exact reason for the issue.

[AScha.3]

Hi,

with serial you will destroy nothing….except you connect other device that has some ESD charge or connection to mains.

But the >motor driver experiments< often end with some “accidently” dead chips.

Most times the result of bad ground or ground loop (power current going through controller board...) or voltage spikes .

-

So with your boards probably you killed some chips...check all boards:

• remove jumper on JP2
• U2 no more red/hot ?
• then check with  CubeProgrammer : can it find the st-linkV3 ?

Is st-link part ok on the boards ?  nothing gets hot ?

[Ozone]

> Only U2 is heating; no other IC is noticeably heating. I replaced U2 with a new IC, but the same problem remains and the replacement U2 also heats up.

The board is most probably a goner.

As suggested, this doesn’t happen just so, and to multiple boards in a row.
I suspect you have connected 5V signals to MCU inputs, with analogue input pins being most susceptible to such damage.

[George Wu]

Try to use alternative power supply source. You can refer to “7.4 Power Supply”. “An external 7 to 12 V power supply connected to CN8 pin 15 or CN11 pin 24”. Good luck!