STLINK-V3SET: Unknown USB Device (Device Descriptor Request Failed) + COM LED flashing red (Brand new unit)

[guguci]

Hi,

I purchased a brand new STLINK-V3SET from a distributor, but it cannot be recognized by the computer.

Symptoms:
- When plugged in normally: COM LED flashes red continuously, the other LED stays solid on
- After shorting the jumper to force DFU mode: only the COM LED flashes red
- Windows Device Manager shows "Unknown USB Device (Device Descriptor Request Failed)"
- Tested on both Windows and MacBook with different USB cables and ports
- Also tested on Windows through a USB Hub, same issue
- No adapter board (MB1440) and no target board are connected
- Even in DFU mode, Device Manager does not show a normal response

Has anyone encountered the same issue? Is this a hardware failure of the USB interface or MCU?

Any suggestions would be appreciated.

Thanks

[AScha.3]

Hi,

usually on Win : no “ding dong” on USB connect means: cable is no data cable or device defective.

So try other USB2 cable, that is tested with other data transmitting device for 100% working.