LED constantly on on 4.1

E

Elf

Well-known member
What does it mean when this LED is always on?
1763507814119.png
 
@Elf: What sketch is running on your Teensy ?? What external hardware do you have connected to the Teensy (is anything external connected to pin 13) ?? Can you load the BLINK sketch & does the LED stay on then ??

Mark J Culross
KD5RXT
 
Nothing is connected to pin 13. It's on even when just connected to the USB port. Blink works but does not turn the LED completely off. Other 4.1s don't show the same behaviour.
 
With that (BLINK does not turn the LED off) new info, a couple of quick possibilities come to mind: 1) The internal drivers for pin 13 are blown (worst case, which can't be fixed), 2) your Teensy has some kind of conductive short (solder ball, metal shard, un-melted solder paste, etc.) that is keeping pin 13 high (inspect your Teensy under high magnification, & hopefully you find something that is easy to remedy). Others may chime in with further possibilities & hopefully, ideas for a fix.

Good luck !!

Mark J Culross
KD5RXT
 
Easy thing to test after p#6 #1 and #2 is the 15 second Restore - pressing the Program button 13-15 seconds until a FLASH of the RED LED - then release and wait for it to stop being RED during the clearing and installing the PJRC factory Blink.

Does the p#13 LED stay on during that - it should not.
Does it show a normal 1 sec blink after that?
 
It's possible. The board is mounted vertically, so not likely. I'm not using pin 13 in my program so I just wanted to be sure there wouldn't be any ill effects.
 
Did you solder a header to T4.1? I'd be looking for solder whiskers/balls between pin13 (LED) and pin14.
Did you clean off the solder flux?
Is T4.1 connected to anything on pin14?

Something is sourcing enough voltage/current to make LED light up. Hopefully it's not a bad GPIO pin.
 
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