Teensy 3.1 seems very hot, pulling 140mA, while another one is only 40mA

[kig]

I've had a very frustrating night fighting all kinds of issues with wiring, etc. I won't bore you with this.

But towards the end, when I was testing the darn seven segment display from Sparkfun (this piece of crap has been my most hated piece of electronics ever produced). in any case, I noticed that when I connect one of my Teensies to the DC power at 5.0V, it starts to get very hot quick, and the current shows 0.14A. The other one, with the same sketch, same connections, does not get hot, and draws 20mA-40mA.

They both have the little connector cut between USB power and VIN, so the power is coming from my variable voltage supply with current limiting.

I am worried about using this hot teensy may result is burning and/or fire. Is there another possible explanation?

Attached is a pic of both Teensies. The left one with the real USB is the one that's heating up. The one where I had to replace the micro USB jack that got ripped off is the "good one".

Any pointers are welcome!

Thanks,
Konstantin

 

[Tomek]

Does the one that get hot communicate ok via serial monitor? Try testing that.

You probably either have
(1) A completely burnt out teensy.

or
(2) A teensy with only a pin or something burn out in ON, in which case you might be able to switch pins and survive.
But if you say it draws that much more outside of any circuit...then you're pretty much out of luck.


Any ideas how it burnt out?

 

[kig]

Just a clarification:

I am able to upload sketches and see the LED blink on both Teensies, so from "functional" standpoint they both work. So I wouldn't say it's "burnt out completely" because it's actually working.

When connected to my variable power supply, the "hot" one draws 160-170mA, while the "normal" one draws 10-20mA.

What else could this be? Is this fixable? Should I not be using the "hot" one in projects, because it might burn and cause fire?

 

[PaulStoffregen]

That's definitely far more current than it should draw.

Perhaps there's something on the board that's putting a heavy load on the 3.3V power line? Maybe a damaged part or some sort of contamination that's conducting, but not a 0 ohm short?

Does it actually measure 3.3V, or something much less?

I definitely would not use that board for an important project.

 

[kig]

That's definitely far more current than it should draw.

Perhaps there's something on the board that's putting a heavy load on the 3.3V power line? Maybe a damaged part or some sort of contamination that's conducting, but not a 0 ohm short?

Does it actually measure 3.3V, or something much less?

I definitely would not use that board for an important project.

Thanks! I haven't had a chance to measure the voltage, but the VIN was at 5V.

At this point I have 2 out of 3 teensies out of commission I ordered a bunch more from OSH, does anyone have any anecdotal evidence that OSH is more (or less) reliable than the stock green one?