Teensy 4.0 input pin accidentally given 4v and now broke

derplecbob

Active member
I accidentally had pin 11 touch a 4v battery wire and now the pin has stopped working on my teensy 4.0.
I know 3.3v is the max voltage.
The rest of the board seems fine and so are the other pins.

Is there a way to fix pin 11?
Or should I cut my losses?
Could I solder on a new resistor on the board or something like that?
 
The 3.3V T_4 has a limited specified tolerance of perhaps 10% over 3.3V toward 3.6V - well below 4V.
So, with luck at hand only one pin is dead, and the reminder of the chip will continue to work as designed for a long usable life.
 
Bad news is there's no practical way to repair a pin damaged this way.

Good news is the rest of your Teensy survived. Often this sort of damage takes out the entire chip. It really depends on the voltage and circuit impedance that tends to limit the amount of current. So at least you can set this Teensy aside for another project not needing pin 11, or (if possible) rewire this project to not use pin 11.

If using a SD card on the SPI pins, you can alternately use pins 26,1,27. Two pins are on the bottom side, so maybe not very convenient, but still technically possible. See the SdFat_Usage example for the special begin() function syntax to use those SPI1 pins.

If you do keep using this Teensy, best to keep in mind it was probably stressed pretty hard, even though it's still working. Might be a good idea to avoid installing it somewhere you can't easily access for replacement if it does later go bad.
 
Bad news is there's no practical way to repair a pin damaged this way.

Good news is the rest of your Teensy survived. Often this sort of damage takes out the entire chip. It really depends on the voltage and circuit impedance that tends to limit the amount of current. So at least you can set this Teensy aside for another project not needing pin 11, or (if possible) rewire this project to not use pin 11.

If using a SD card on the SPI pins, you can alternately use pins 26,1,27. Two pins are on the bottom side, so maybe not very convenient, but still technically possible. See the SdFat_Usage example for the special begin() function syntax to use those SPI1 pins.

If you do keep using this Teensy, best to keep in mind it was probably stressed pretty hard, even though it's still working. Might be a good idea to avoid installing it somewhere you can't easily access for replacement if it does later go bad.
Thank you for your help :)
It seems the teensy is working perfectly, it’s just pin 11 is not functional. I’ll switch to pin 12 as it’s not too important that I use pin 11.
 
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