teensy gets very warm

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AgentDuck
 
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teensy gets very warm

Post by AgentDuck »

I recently plugged in my teensy LC and the arduino IDE could not find its USB port. I touched the larger microchip at the back and it burned my finger.

Code: Select all

Arduino: 1.8.15 (Windows 10), TD: 1.55, Board: "Teensy LC, Serial, 48 MHz, Smallest Code, US English"

Sketch uses 6708 bytes (10%) of program storage space. Maximum is 63488 bytes.

Global variables use 1740 bytes (21%) of dynamic memory, leaving 6452 bytes for local variables. Maximum is 8192 bytes.

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

Please press the PROGRAM MODE BUTTON on your Teensy to upload your sketch.

Board at usb:0/140000/0/2 is not available
pressing the upload button on the teensy does nothing

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adafruit_support_mike
 
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Re: teensy gets very warm

Post by adafruit_support_mike »

That strongly suggests a short circuit in the microcontroller.

Post a photo showing your hardware and connections and we'll take a look. 800x600 images usually work best.

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AgentDuck
 
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Re: teensy gets very warm

Post by AgentDuck »

teensy and its circuit
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I labeled the teensy pins in red, the 5v and gnd pins look like they are in contact but they are not, the program pin, however, is connected to the ground pin on accident. I didnt fix this because I didnt think it would be a problem, and the teensy already wasn't connecting to the computer before I soldered them together
I labeled the teensy pins in red, the 5v and gnd pins look like they are in contact but they are not, the program pin, however, is connected to the ground pin on accident. I didnt fix this because I didnt think it would be a problem, and the teensy already wasn't connecting to the computer before I soldered them together
watch circuit.jpg (231.65 KiB) Viewed 517 times
teensy overview.jpg
teensy overview.jpg (185.07 KiB) Viewed 517 times

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adafruit_support_mike
 
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Re: teensy gets very warm

Post by adafruit_support_mike »

It’s hard to tell with the blurring, but some of the solder joints on the Teensy look like they’re pinched in at the bottom. That’s often a sign of a poor connection to the pad.

The wiring on the underside of the board has a lot of red flags as well. First, it looks like the wire you’re using is larger than you need, and the extra bulk is making things harder for you. For any current less than 2A, 24-gauge phone wire is large enough. For low-current logic signals, 30-gauge wire is plenty, and is easy to work with.

It’s also a good idea to use solid wire with pad-per-hole board. Multistrand wire doesn’t bend well (which is good for connections that need to move), which means you have to fight with it over short distances.

Next, it looks like the solder was kept hot after the flux burned off. Molten solder oxidizes when it touches air, and the oxide layer breaks down into powder that mixes into the liquid metal. That makes the solder pasty and hard to work with.

Flux is made from organic acids that aren’t active at room temperature but become aggressive at soldering temperatures. They dissolve the oxide, and float on top of the molten solder as a protective layer that keeps air out. The acids also burn at soldering temperatures, so the flux layer only lasts a few seconds. The telltale sign of solder that needs more flux is the formation of ‘horns’.. points where the solder clings to the iron as you pull it away. Well-fluxed solder snaps back to a smooth surface when you pull the iron away.

Given the number & issues, there’s a strong chance one of the GPIO pins got shorted to VCC or GND somewhere along the way.

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AgentDuck
 
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Re: teensy gets very warm

Post by AgentDuck »

thank you for the help :D

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