Teensy 4.1 not responding

Development Boards Teensy
1

Hi everyone,

I recently bought a Teensy 4.1 from PiHut. When it first arrived, I tested it, and serial communication seemed to work fine. However, after that initial test, the board is no longer recognized by my PC at all.

Here’s what I’ve tried and observed so far:

  • I checked all adjacent pins for shorts; there are none.
  • I attempted to power the board independently via the soldered 5V pin—nothing happens.
  • The USB cable works perfectly with all other devices, including a 1TB external drive.
  • Pressing the program button while plugging in the board causes the red LED to blink continuously, but the board still isn’t recognized by either my PC or the Teensy Loader.
  • I measured the voltage on the VIN and 3.3V pins:
    • Initially, there was no power on the 3.3V pin.
    • Now, with the LED blinking, there is power on both the 5V and 3.3V pins.

It appears that the board might be bricked, and I don’t understand why this would happen since it was still running the initial simple serial communication test code.

Has anyone encountered this issue or have suggestions on how to recover the board? Any guidance would be much appreciated.

Thanks in advance!

2

Red LED continuous blink when holding program button at power-up. This is the bootloader’s “waiting for code” state. Normally, the Teensy Loader should be able to detect the device in this state (it shows up as a HID device, not as a COM port).

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3

Thank you. For some reason the Teensy just started working again but the behaviour is erratic, sometimes it says device connected malfunctioned. Also when connected to any USB ports it mutes any audio playing. I tried changing changing settings via Arduino IDE > tools > USB type > serial but on the board/COM selector it keep showing as “COM8 Serial+MIDI+Audio Teensy Ports”. It still responds to the simple serial comm test currently running however.

Could this be a problem with the hardware or software?

4

It can be a bad USB cable/loose USB connector.

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