Teensy 3.6 problem - The chip is very hot

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Hello. I have a problem with my teensy 3.6. It is very hot that I can't touch it by hand even though I've just plugged it to USB cable for just a few seconds. The upload code is very simple, (I already tested with the other board, it is ok). The chip which connected to pin D- and D+ pin is very hot.
Are that normal phenomena?
If no, what should I do to fix it?
Thank you very much
 
Very hot is a bit relative - though too hot to touch is a bad sign - that is not normal. The Main MCU chip is spec'd to run when 'too hot to touch' - but nothing else should generally unless there is a great deal of 3.3V current in use - and the input voltage is higher that USB voltages the voltage converter chip could get that warm without damage.

As Frank B cross posted - the T_3.6 has likely suffered damage and is likely broken

Since it is plugged in to USB - perhaps there is no external power on Vin and the VIN<>VUSB jumper on the bottom is still in place?

Is/was anything connected to the Teensy? Has it been soldered with pins or other devices?

There are two pairs of pins on T_3.6 with D+ and D- labels - one pair of pads on the bottom side edge under the device USB connector and one pair of pin holes internally for the USB Host support - so not sure which chip might be referenced - perhaps the ones with traces from the device connector that is 'literally' connected ? The 5V to 3.3V Power converter chip might be the one hot - but it connects to the GND and 5V of the USB connector?
 
Very hot is a bit relative - though too hot to touch is a bad sign - that is not normal. The Main MCU chip is spec'd to run when 'too hot to touch' - but nothing else should generally unless there is a great deal of 3.3V current in use - and the input voltage is higher that USB voltages the voltage converter chip could get that warm without damage.

As Frank B cross posted - the T_3.6 has likely suffered damage and is likely broken

Since it is plugged in to USB - perhaps there is no external power on Vin and the VIN<>VUSB jumper on the bottom is still in place?

Is/was anything connected to the Teensy? Has it been soldered with pins or other devices?

There are two pairs of pins on T_3.6 with D+ and D- labels - one pair of pads on the bottom side edge under the device USB connector and one pair of pin holes internally for the USB Host support - so not sure which chip might be referenced - perhaps the ones with traces from the device connector that is 'literally' connected ? The 5V to 3.3V Power converter chip might be the one hot - but it connects to the GND and 5V of the USB connector?

I added 3 pin header a10. A11. Aref. That all i did with this board. But didn't connect to anything. No other power source, but usb.
 
Bare Bones Sketch

Let the board cool down. Remove any SD Card or other attachments. Then attach to the USB socket and try running the attached "Bare Bones" sketch on your T3.6.

It will flash the LED four times quickly on startup, then flash the LED twice every second.

If you type "A" at the Serial Monitor, after a very short delay, it should print out the current value of "LoopCount" (which increments every second).

It should run the T3.6 as "cool as a cucumber". If not then there is a fault with the board (or your USB 5 volts supply may be too high - try measure it).

Make sure the joints you soldered on the board have no bridges.

Code:
//BareBones - Test sketch for Teensy
//==================================
//Author: TelephoneBill
//Date: 15 JUL 2019
//NOTES: Minimum sketch to test basic operation.

//definitions
uint32_t LoopCount;
byte Byte1;

//SETUP CODE
//==========
void setup() {
  //initialise general hardware
  Serial.begin(9600);                        //setup serial port
  pinMode(13, OUTPUT);                   //pin 13 as digital output
  FlashLED(4);                                //flash four times, just for confident startup
}

//MAIN LOOP
//=========
void loop() {
  //call KeyInput() routine
  KeyInput();                                 //type "A" to see value of LoopCount
  FlashLED(2);
  delay(1000);
  LoopCount++;
}

//SUBROUTINES
//===========
//Flash LED routine
void FlashLED(int m) {
  for (int n=0;n<m;n++) {
    digitalWriteFast(13, 1);
    delay(100);
    digitalWriteFast(13, 0);
    delay(100);
  }
}

void KeyInput() {
  //process any keystrokes available
  if (Serial.available()>0) {
    //read the incoming byte
    Byte1 = Serial.read();
    if (Byte1>0x20) {
      switch (Byte1) {
      case 'A':  //type to see value of LoopCount
        //task goes here...
        Serial.print("LoopCount = "); Serial.println(LoopCount);       
        break;
      }
    }
  }
}
 
Let the board cool down. Remove any SD Card or other attachments. Then attach to the USB socket and try running the attached "Bare Bones" sketch on your T3.6.

It will flash the LED four times quickly on startup, then flash the LED twice every second.

If you type "A" at the Serial Monitor, after a very short delay, it should print out the current value of "LoopCount" (which increments every second).

It should run the T3.6 as "cool as a cucumber". If not then there is a fault with the board (or your USB 5 volts supply may be too high - try measure it).

Make sure the joints you soldered on the board have no bridges.

Code:
//BareBones - Test sketch for Teensy
//==================================
//Author: TelephoneBill
//Date: 15 JUL 2019
//NOTES: Minimum sketch to test basic operation.

//definitions
uint32_t LoopCount;
byte Byte1;

//SETUP CODE
//==========
void setup() {
  //initialise general hardware
  Serial.begin(9600);                        //setup serial port
  pinMode(13, OUTPUT);                   //pin 13 as digital output
  FlashLED(4);                                //flash four times, just for confident startup
}

//MAIN LOOP
//=========
void loop() {
  //call KeyInput() routine
  KeyInput();                                 //type "A" to see value of LoopCount
  FlashLED(2);
  delay(1000);
  LoopCount++;
}

//SUBROUTINES
//===========
//Flash LED routine
void FlashLED(int m) {
  for (int n=0;n<m;n++) {
    digitalWriteFast(13, 1);
    delay(100);
    digitalWriteFast(13, 0);
    delay(100);
  }
}

void KeyInput() {
  //process any keystrokes available
  if (Serial.available()>0) {
    //read the incoming byte
    Byte1 = Serial.read();
    if (Byte1>0x20) {
      switch (Byte1) {
      case 'A':  //type to see value of LoopCount
        //task goes here...
        Serial.print("LoopCount = "); Serial.println(LoopCount);       
        break;
      }
    }
  }
}

It worked, but still very hot. I already check the USB line with other teensy board, it is ok. I already remove a new pin header to make sure, but still the same.
 
It worked, but still very hot. I already check the USB line with other teensy board, it is ok. I already remove a new pin header to make sure, but still the same.

Good that it seems to be functional - a pic with indicator of the heat affected chip would allow understanding beyond - there is a short somewhere - or it was damaged and waiting to fail.
 
By coincidence, I have the same issue with a brand new Teensy 3.2. It came with headers, so all soldering looks good.

I tested it with the BareBones code, powered from a pc usb, without any hardware attached and the temperature was fine. However, I measured the voltage over the GND and 5V pins, and it was only 2.16V. So there must be something wrong with the board.
 
I had the very same problem and my Teensy 3.6 was pretty much new. The chip you were talking about is the TPD3S014 which is a Current-Limit Switch and D+/D– ESD Protection for USB Host Ports. So if you're not using an extra usb Port (those Pins you were mentioning D+, D-...), this chip is basically useless. I carefully removed it with my soldering iron and the Teensy keeps working like a charm.

(by the way: this chip wasnt even used on the Teensy 3.5: look at: https://www.pjrc.com/teensy/schematic.html ) ;)
 
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