Did I just fry my teensy 3.6?

[sargentpilcher]

I got the error "Teensy did not respond to a USB-based request to enter program mode." I've followed all the trouble shooting steps (USB cord, program button, etc.) when I got to reason #3: "Dead (usually overheating) Main Chip: More than 4 volts applied to the 3.3V power pin instantly kills a Teensy LC or 3.2. Be extremely careful if connecting circuits to Teensy using both VIN(5V) & 3.3V pins, or when using any external power supply. Loose wires between Teensy and other electonics accidentally touching are the most common way Teensy fails. "

It doesn't feel hot in any way, but it was JUST working 5 minutes ago. I have a proto board that I purchased and I've spent all day soldering to it. I have a project with LED lights and molex connectors, and I got 1 strip of LED's to work, but it's going to be a total of 8 strips. So I wired the 2nd one together, but it didn't work. I grabbed my multi-meter and started checking for bad connections, and found a bad ground connector. However, as I was testing, I checked to see if there was cross talk between wires, and was surprised there was when my multi-meter started beeping. I then discovered that the "cross talk" was not because my multimeter was detecting its own voltage, but the computer voltage, because it was still plugged into the USB port, so I unplugged it and kept going. I fixed the ground connector, and plugged it back in, but it hasn't worked since.

By using my multimeter to check this way I would have sent voltage to pins 35, 36, 37, and 38 along with the voltage pin and ground pin.

Is it fried off of just USB power? I know USB is 5v and it says above that's indeed enough to fry it. But jeez, I wasn't expecting that. It's a good learning experience if that is indeed the case. Can anybody confirm for me that I fried my Teensy? Or should I try something else?

 

[PaulStoffregen]

The USB power goes to a 3.3V regulator on the board, so 5V power from USB doesn't kill the board. At least not unless you do something like touch a wire between VIN and 3.3V.

 

[sargentpilcher]

I don't THINK I did. I can't rule it out 100%, but I all I remember checking were pins that were associated with my current project, like the pins I listed above (VIN is not used in my project). Would there be a way to double check if I had? I went through the troubleshooting guide on your website for this issue, but none applied.

The Most Common Problems
#1: LED Blinks But No USB Communication: Many cell phones are sold with charging-only cables. They have only 2 wires for power, but are missing the 2 data wires. Try another USB cable, ideally one known to work for USB.

My LED doesn't even blink.

#2: No COM Port or Serial Device Seen: Teensy uses HID protocol for uploading, not serial. Brand new Teensy boards are shipped with the LED blink example compiled to appear as RawHID. You must program Teensy at least once from Arduino. The COM port (Windows) or Serial Device (Mac, Linux) appears only after Teensy begins running your program. Regular Arduino boards are always serial. Teensy uses HID and supports many protocols. To use serial, make sure the Tools > USB Type menu is set to "Serial", and understand Teensy only becomes a serial device when it runs your program built with this setting.

I'm not going to pretend I understand this, but I don't think it applies to me as I'm doing USB in MIDI mode. Not to mention the fact that it was JUST working.

#3: Dead (usually overheating) Main Chip: More than 4 volts applied to the 3.3V power pin instantly kills a Teensy LC or 3.2. Be extremely careful if connecting circuits to Teensy using both VIN(5V) & 3.3V pins, or when using any external power supply. Loose wires between Teensy and other electonics accidentally touching are the most common way Teensy fails. Just a few extra minutes to cover exposed leads and mechanically secure loose wires, especially if they can easily unplug from a solderless breadboard, can save you from an unpleasant and costly "learning experience".

I thought this was the reason, but you have given me a new hope

Unreliable Communication
Some USB hubs have trouble handling the rapid sequence of connect/disconnect events when programming Teensy. Most hubs work fine, but the few that do not can cause very strange problems. If you experience trouble, always try connecting Teensy directly with a quality USB cable.

It's the same USB cable that has worked for me dozens of other times.

When I hit the reprogram button, nothing happens.

Thank you so much for your help!

 

[sargentpilcher]

I decided to try updating my teensyduino software and the arduino software. I'm on windows 10, and now I'm getting a new error message that says

"No Teensy boards were found on any USB ports of your computer."

If I try to select the port for communication, the only option is "emulated serial".

 

[sargentpilcher]

Ok, I took my teensy out of my proto board (Man that was a pain desoldering everything.). It works outside of the proto board. I think I have a short somewhere.

 

[PaulStoffregen]

It works outside of the proto board.

At least that part is good news.

If you have a current limited power supply and a voltmeter with sensitive mV scale, one fun way to search for a short is to set the power supply to a fairly low voltage and moderate current limit. Connect it to the shorted power lines and turn the current up as much as is safe for the wires. Then start measuring voltages between points. If current is flowing through the wire, you'll see maybe a couple mV drop along a segment of the wire. By poking around to see where the current is and isn't flowing, usually you can narrow down where the short must be.

 

[sargentpilcher]

Thank you so much for your help! That was a great idea! I found the short! Now I'm running into other unrelated problems. I don't know if I damaged the board or what, but it's not working right. I need to step away from this for a little bit as I'm not thinking clearly about it anymore. Thanks again for your help!