Think my brand new teensy is dead

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gregchill

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I was working away on my Teensy witch i got just a couple of weeks ago. when plugged in the USB stop been reconised by the device manager the on board led light stopped.
I previously had a problem with 2 of the pins and found out the we outputting nothing.
I got on to the Arduino online shop where i bought it and they have reverted be back here.

Is there anything i can try?
 
Try reloading the blink program back into the teensy. I know you can not see it as a port, but the ide should send the info to the teensy is it is seen. I know when I make my boards here and need to install the specific programs, the teensy are not seen on the usb bus, but after they are programmed, they show up. This will simply be a test to see if the teensy has an issue..
 
First, for troubleshooting, disconnect your Teensy from other circuitry.

The normal troubleshooting tips are here:

http://www.pjrc.com/teensy/troubleshoot.html

If you want us to help here, you must tell & how us what you've actually done. I may be assuming too much, but from what little you've written so far, you're telling us what you think you did or what you meant to do. That's great when everything works, but when things go wrong, there's very little anyone can do if you don't show precisely what was actually done.
 
Hi,

i plugged it in to the usb with nothing else and im getting 0 voltage readings on any of the pins except the vusb pin, 5 volts.
I had my doubts it was faulty all along with not being able to transmit midi on Tx1 and i think there was a problem with the way the eeprom was reading the code i had, but i am new to the Teensy and thought it maybe more software than hardware based.
 
Does "im getting 0 voltage readings on any of the pins except the vusb pin" mean there's no voltage on the 3.3V pin?

When you first used Teensy, the LED should have been blinking before you uploaded your own code. We test every Teensy here, using a bed-of-nails test to check every pin, and then a test with a USB cable to a Mac, which programs the LED blink. If your Teensy blinks when you first use it, that means it worked here when it was connected to the Mac we use to test every board and load the LED blink.

I can tell you the most common cause of hardware failure on Teensy 3.1 was exceeding the 5.5V maximum voltage. If that power supply you're using ever had more voltage, such as spikes during started, it could easily kill your board.

On Teensy 3.2, we started using an external regulator chip, which comes with its own trade-offs, but it's able to withstand up to 10V.
 
HI,

Yes no voltage off any of the 3.3v pins, yes the Teensy 3.2 led did blink when i got it first,
The Teensy was coming off the 9v power supply to a 5v converter circuit so was a 16x2 led screen, (if it had been a spike which is possible) wouldn't the led screen got blown as well.
As i said before i was having issues with it , i just didn't use the two pins that were not working ,and it was happy working away plugged into the usb and the computer suddenly gave an error message of usb device not recognized.
 
Are you also getting zero volts at VIN? Normally VUSB and VIN are joined together, so they should have the same voltage. Unless the pads were cut apart on the bottom side. If so, you'd have to join them back together to run the board from only USB port.

No voltage at all on 3.3V is definitely bad hardware. Absolutely zero volts is really unusual. Usually when the hardware has died, there's something like half a volt. Then again, completely 0 volts could be an actual chip failure. Very hard to be 100% certain.

But not getting 3.3V is absolutely a dramatic hardware problem. This isn't something can just magically happen by itself in the normal course of uploading code. I know it might seem that way because we don't know what really happened, but because of how the hardware works, that 3.3V is from a regulator that defaults to on, so no code or other steps are needed. Then the MK20 chip gets 5V power, its regulator circuitry creates the 3.3V. It's all hardware.

Regarding over-voltage, I can tell you these newer 32 bit chips are much more sensitive than older chips like the ones used on character-only LCDs. If overvoltage did kill your Teensy, it's quite possible other stuff able to handle more voltage survived.
 
Are you also getting zero volts at VIN? Normally VUSB and VIN are joined together, so they should have the same voltage. Unless the pads were cut apart on the bottom side. If so, you'd have to join them back together to run the board from only USB port.

I'm wondering if the OP had both USB and external voltage connected (to Vin) at the same time somewhere along the line, without cutting the trace on the bottom. That could explain the behavior I think is being described here.
 
Hi,
i had cut the trace to run external power as instruction.
With the trace back together.
Vin and VUSB are reading 1.7 volts.
and the 3.3v is reading 0.6.

The 9V power supply was plugged into a surge protection plug board but how well they work could be debateable.
 
Sorry for kidnapping this thread but i have another question about Teensy hardware failures:

If a defective teensy 3.0/3.1 is getting hot when plugged in USB and draws around 30mA without peripherals, what could this typically be? Having now two of them.
For my application i use no USB, the VIN/VUSB is cut and Teensy is powered from 12V AGL via DC-DC down to 4.4V to be compatible with GPRSbee.
I suspect some ESD problems because the device is very exponated and some outages are accepted/expected.
 
30 mA at 5 volts is only 150 mW. That's only enough power to slightly warm the chip.

If it's getting hot to touch, it'd have to draw a *lot* more than just 30 mA.

Teensy 3.0 & 3.1 are very sensitive to anything over 5.5V. Sadly, quite a lot of power supplies create over-voltage spikes, especially switchers. Small DC-DC converters often require external capacitors for good start-up behavior.

The main reason we went from 3.1 to 3.2 was to use a much more robust external regulator chip that can handle 10 volts. Even though this has some downside for extremely low power use (the regulator chip always draws some power), it makes the whole board much more rugged for hobbyist usage.
 
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