Did I fry my Teensy?

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BuffaloFan32

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I was running the VideoDisplay script on two Teensy 3.2's and suddenly everything went blank. Upon restarting, I was unable to run the script again. It seems like the computer is not seeing the Teensy's as no new COM ports appear when I plug them into the USB port on my Windows laptop. I have another Teensy that I can plug into the computer using the same cable and it is recognized right away. Any idea what could have killed my Teensy's? At the time of failure, only one of the Teensy's was connected to the computer but they were both connected to my LED display. Both of them are soldered to Octo adapters and have their VIN pads cut so they are powered by the power supply that is powering the LEDs (the separate test Teensy is not connected to the LED array in any way). I tried uploading the Blink script to the dead Teensy's even though no COM port was available but it did not seem to work. Should I try anything else?

I am now afraid to connect my other Teensy's to the display. Any ideas on how to track down the problem? I am a novice so I do not have any formal training on these issues.

Any suggestions on how to protect the Teensy's from this happening in the future? I have a fuse in between the power supply and the positive terminal of the bus bar but I guess it did not blow. That brings up another question that I have, sometimes I see people put a capacitor or a resistor between the Teensy and the LED strip, do you still need to do either of those things if you are using an Octo adapter?

Is there any warranty on the Teensy or the Octo?

Thanks for your help!
 
Disconnect everything from the Teensy. Then establish the Usb-Vin link again, so that the nude Teensy without any peripherals can be connected to the PC. If you have luck, it will show up immediately. If not try the restoration procedure:

A previously working board may seem to be dead, but the problem may simply be code on your Teensy which confuses your PC's USB port.
Physically disconnect the Teensy.
Reboot your computer (complete power off is best)
Make sure the Teensy Loader application is running.
Hold the reset button down, before plugging in the USB cable.
Plug the USB cable in while continuing to hold the button.
After the cable is fully inserted, release the button.
Of course, verify that your USB port and cable are working properly, perhaps with a different USB device.
On Windows systems, "strange" problems are occasionally reported, where Windows will not detect new devices. It does not seem to be unique to Teensy. Creating a new user account sometimes solves the problem. Plugging the cable into different USB ports can also help. Rebooting is always a good idea. The best approach is to try on a Mac or Linux machine, or a different Windows machine.
 
Thanks @Theremingenieur! How do I establish the Usb-Vin link again? Is it difficult to separate the Teensy from the Octo? Are you in France?
 
If the Teensy is soldered directly to the Octo board (by header pins), separating the 2 may not be feasible. Desoldering pins properly is very difficult. Almost everyone who attempts this ends up damaging the boards. Desoldering usually involves much more heat and mechanical stress than the boards can tolerate. Broken traces and lifted pads are a common problem.

If the 2 boards are permanently joined, probably the best you can do is unplug the CAT5 cables. If you've added any *other* hardware, try disconnecting that stuff, so it's only the Teensy and Octo board.

Of course, if you used these sockets, then you can just unplug the Teensy. If this hardware does end up being a loss and you have to start over, get those sockets for the next try. Being able to unplug the Teensy makes troubleshooting much easier.

Both VUSB and VIN are through-hole pads, so you can reconnect them using a wire from the top side of the board. That will let you power the Teensy from USB.

With Windows, you might use the Device Manager to see whether Windows is detecting *any* hardware change at all when you plug in the Teensy. A cold reboot, including power cycling any USB hubs, is also a good idea. Sometimes "strange" USB problems can cause a port or hub to stop working until the hardware is reset.

Also try the troubleshooting guideline where you hold the Program button when plugging in the USB cable. If the code on Teensy is corrupted, this will prevent it from running and when you release the button, Teensy will run the bootloader (which is a HID device - not a COM port).


Is there any warranty on the Teensy or the Octo?
Click to expand...

Warranty is about manufacturing defects. If we made a mistake and the product was defective due to our fault, then we do replace it.

But warranty isn't an insurance policy against mistakes and accidental damage. With a product like Teensy, this can be tricky. The reality of DIY electronics is pretty much everything done with Teensy is the sort of hardware modification which would immediately void the warranty on any ordinary consumer product. Robin & I try to use good judgment. But I can tell you, in cases like this where the Teensy was working and was damaged by connecting to a large LED project involving external power supplies, warranty for manufacturing defects generally does not apply.
 
I’m in France, yes.

But I can’t understand your question. You must have cut the Vusb-Vin trace and you must have soldered or plugged the Teensy and the Octo together. Now make the similar steps in reverse order to put the Teensy back into factory state. That can’t be too difficult. If you could do it one way, you must also be able to revert everything...
 
@PaulStoffregen, I did try disconnecting the CAT5 cables and holding the Program button while plugging in the USB cable but the Teensy was still connected to the power supply that was also connected to the LEDs (not sure if that would cause a problem). When you say that the Teensy will run the bootloader, what does mean? Nothing happened on my computer screen. Is that the program that appears when I am using my Arduino software? Is there some other way to see if an HID device has been added to my computer? I should add that I tried this on two laptops.

As far as the sockets go, I am now using those instead of the permanent pins that I was using in the beginning.
 
BuffaloFan32 said:
When you say that the Teensy will run the bootloader, what does mean?
Click to expand...

This means Teensy will not run anything at all while you are holding the button. The main MK20 chip held in the reset state, until you release the button.

When you do release the button, assuming the hardware isn't damaged, Teensy will run the bootloader program rather than trying to run whatever code you previously programmed. If that code is somehow corrupted in a way that's messing up the USB port, doing this allows you to start with the known-good bootloader.

If the hardware is damaged, or if the board isn't getting power, or it your USB cable is bad, then you'll see nothing happen on the PC side. But if the board does have 5V power from the USB and you can measure 3.3V power on the 3.3V pin, and the USB cable is good (easy to verify by using it with a known-good USB device), and you *still* get nothing, then you can conclude the Teensy is almost certainly destroyed.

The reason for holding the button is to eliminate the possibility that a corrupted program is disrupting USB communication (causing Teensy to falsely appear to be dead). That scenario is rare, but it can happen, especially with the Windows USB drivers that are not as robust as Linux & Macintosh. This is why I recommend to cold-reboot your computer and power cycle any USB hubs, so you can do the test with a freshly rebooted PC, then plug the Teensy in while holding the button, so that fresh PC never sees Teensy run the old code.
 
So, the Teensy's still work! Upon taking my setup apart, I found that one of the CAT5 cables that was plugged into an Octo had melted. Any idea what could have caused this? If it is a short in my array, how can I track it down?

usb.jpg
 
My guess is you've got one or more of the CAT5 white wires that should connect to GND actually connected to the +5V power. That's the only mistake I can imagine causing enough current flow to melt the connector.
 
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