Teensy 3.0/3.1 unresponsive and overheating?

Status
Not open for further replies.
Q

qtong

Member
I had my array of 60x32 leds working well from the octows2811 library when moments (30 minutes?) after everything worked, one of the teensys overheated and stopped working. I assumed that some of the wires touched the wrong part of the teensy causing it to overheat.

Then comes the teensy 3.1 where I payed special attention to the wiring and the same thing happened! When I try to upload a program, the compiler says something along the lines of having to press the refresh button to load, however, the refresh button is unresponsive. When I desolder everything and plugged the teensy directly to my computer, it heats up rather quickly with the same error message.

My other teensy that's worked flawlessly is actually powered by the 5v psu without having the vin/vusb cut. I've tried powering the other teensy in several different ways but still no response. I'm sure it has something to do with my wiring?
 
I wish I could tell what's causing these problems, but from only this text it's impossible to know.

One thing that really helps is those series resistors on the 8 pins. Even just 68 or 100 ohms really helps protect Teensy from trouble.

Another thing that's caused some blown Teensy3s is bad power supplies. The most common problem is with ATX computer power supplies used for only 5V. Many of them are designed with the assumption of heavy usage on the 12V lines. A least a couple people have found their supposedly high quality (well known brand name) ATX supply produced horrible 7V or higher spikes (visible only with an oscilloscope) on the 5V line when 12V was unused.

But really, those are just blind guesses.
 
PaulStoffregen said:
I wish I could tell what's causing these problems, but from only this text it's impossible to know.

One thing that really helps is those series resistors on the 8 pins. Even just 68 or 100 ohms really helps protect Teensy from trouble.

Another thing that's caused some blown Teensy3s is bad power supplies. The most common problem is with ATX computer power supplies used for only 5V. Many of them are designed with the assumption of heavy usage on the 12V lines. A least a couple people have found their supposedly high quality (well known brand name) ATX supply produced horrible 7V or higher spikes (visible only with an oscilloscope) on the 5V line when 12V was unused.

But really, those are just blind guesses.
Click to expand...
Paul,

I have the 220ohm resistors in the 8 pins and use the 5v psu's purchased from ebay. From what I can see, my set up at this point is nearly identical to yours. The one difference is that in the teensy that's been working without flaw, I did not cut the vin and vusb pads apart. They are still intact and that teensy is connected to the psu via the +5v pin.

noob question but when you refer to cutting the pads apart, it's just with an x-acto knife cutting the surface?
 
@qtong:

noob question but when you refer to cutting the pads apart, it's just with an x-acto knife cutting the surface?
Click to expand...

If you look at the bottom of the link: https://www.pjrc.com/teensy/teensy31.html

You can see that the pads are connected to each other, so I do believe that you would need an X-Acto knife to cut the middle trace between Vin and VUSB. This will separate it.

It looks like that the new Teensy 3.1 board does support 5V Input on the Digital Pins, you will still need a buffer as the output on the pins is 3.3V.

From the OctoWS2811 page:
Teensy 3.0 (and 3.1) should be powered by the same +5 volt power supply as the WS2811 LEDs. By default, Teensy 3.0 has VUSB connected to VIN.
They can be separated by cutting apart pads on the bottom side of the board (note how the picture on the page, there is no middle trace).
So now the board will now be powered by VIN, not VUSB.
Once cut apart, it is safe to apply +5 volt power to VIN. The USB cable will not attempt to power the LEDs, and the power supply will not feed power back to your computer.

When Teensy is powered by VIN, you can only load new code when VIN has power, because VUSB is disconnected.


I have a question:
So if I cut the bottom pads, so I can power the Teensy from the same LED PSU, can I still connect the Teensy to my PC via USB and it will be recognized by the PC so I can load code to it?
So hear me out - USB just only now needs to send the signals and does not need to power the board as the board is getting power from the PSU. So the Teensy will be recognized by the PC as long as it has power?

I just wanted to make sure that I understood the last part of the Teensy being powered by VIN from the OctoWS2811 page.
 
I'm having the same problem. Went through two in two days. I cut the pads on both and everything worked fine for 3 hours or so. Then...nothing. I checked the Teensy and it was too hot to touch. Swapped it with a new one. Fine for 2 days. Then dead.

In my case, I'm using the Teensy 3.1 hooked up to a strand of NeoPixels. Power is supplied by a switching power supply to a breadboard where it's connected to the Teensy and the NeoPixels.

I've got one more 3.1 in the studio and would really prefer not to burn this one. Any ideas what could be causing this?
 
Strangely I think I've had the same problem..I've been playing with my t3.1 for a few weeks. I was prototyping on another part of the breadboard and I had some magic smoke escape from a transistor. My teensy from then on was no longer functioning.
I had no I/O on the teensy hooked up only GND and 3v3 from a SMPS, my current theory is that I over drew my SMPS and caused it to saturate the inductor and possibly give an unstable voltage source - maybe over-volting the teensy?

Either way its dead -- hooking it up to my bench supply at 3v3 it tries to draw ~2A and the chip becomes blisteringly hot, with no USB activity to speak of.

Paul, would it interest you at all to have the part sent back for diagnostics?

Cheers
 
this happened many time to me too (broken teensy 3.1 + super hot), without being able to track down the exact problem source.

in my setup i provide 5v to the VIN pin via this OKAMI dc/dc converter: http://www.digikey.ca/product-search/en?x=0&y=0&lang=en&site=ca&KeyWords=811-2692-ND
in addition i have a diode between VIN and the output of the converter. i used the diode because when i connect usb and upload new code, i do not want the usb power to exit through the VIN pin in to the dc/dc converter.
all my digital pins are outputs and send PWM signals to custom LED drivers.

i will try different dc/dc converters and add 68-100 ohm res in series will my output pins.
 
Status
Not open for further replies.
Back
Top