Servo/PWM Pi hat overheating and smoke

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Fane
 
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Servo/PWM Pi hat overheating and smoke

Post by Fane »

Hi!
I recently purchased a servo hat( 16 channel x 12 bit PWM) for my raspberry pi 3 and when connected to a power supply the transistor that is next to the supply port gets really hot and starts to smoke after 30 seconds. I use a adjustable power supply that i set to 5V and it has 1A current. Do you have any ideea why this is happening?

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adafruit_support_rick
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Please post clear, detailed pictures of both sides of the hat, showing your soldering and wiring

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Fane
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by Fane »

http://imgur.com/a/HdITo

Hope these help. I tried my best to sodder the pins.

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adafruit_support_rick
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Thanks for the pictures.

That soldering will not work. In a good solder joint, the solder flows completely over the pad and up the pin, like this:
Image
You have to touch the iron to both the pad and pin to heat them both evenly, then apply solder.

Please review our soldering tutorial:
https://learn.adafruit.com/adafruit-gui ... ring/tools

Overheating and smoke is a sign of a short-circuit. Make sure that your solder doesn't bridge between two pins.
It can also be a sign that you have applied too high a voltage to the board. How are you powering the board?
If you saw smoke, then unfortunately the board is probably damaged beyond repair.

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Fane
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by Fane »

i used a variable power supply that i set at 5v and has 1 amp current( like a wall mount charger). it didn't look like anything what touching. my arm was shaking after 10 minutes of trying to solder :)
thanks for the reply!

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adafruit_support_rick
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Well, fix the soldering and we'll see what happens. Post some more pictures when you're done.

Do you know which chip the smoke was coming from?

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Fane
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by Fane »

The smoke was coming not from a chip but from the transistor that is next to the power supply port.
http://i.imgur.com/JNDXAAY.jpg
The part circled in yellow was the source of the smoke.

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adafruit_support_rick
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Check the polarity of the power supply you have connected to the hat. I'm thinking that you have positive and ground reversed, and that's what burned out the transistor.

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FesterWerks
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by FesterWerks »

I finally got around to using the Servo hats I ordered back in March. I'm having this issue with all three of them. I'm using the recommended power supply with the barrel jack (5v2a. I've used 2 different supplies with the same result. I've bubbled 2 of them and the 3rd would fry if I left it plugged in more than 20 seconds. My soldering I'm sure isn't perfect, but this is what one of them looks like. Any suggestions on where to start troubleshooting?
IMG_1357.JPG
IMG_1357.JPG (833.76 KiB) Viewed 433 times

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adafruit_support_rick
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Two of the boards burned? Are you sure the PS polarity is correct? Which part burned up? What servos are you using? What model?

Soldering looks passable. That wouldn't cause the board to smoke anyway.

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FesterWerks
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by FesterWerks »

Yes 2, I've attached pics of the 2 that burned, same part on each which I think is a power regulator, just behind the barrel jack connector. I am using this power supply straight out of the box, no mods ( https://www.adafruit.com/product/276 ). I haven't connected any servos, as I'll be using these to control LEDs. This happens without the board plugged into the rPi as well.
IMG_1358.JPG
IMG_1358.JPG (744.16 KiB) Viewed 425 times

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Re: Servo/PWM Pi hat overheating and smoke

Post by adafruit_support_rick »

Seems like you must have a bad power supply.
Please email [email protected] with a link to this post for a replacement power supply, and two replacement servo hats

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buddhabandit
 
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Re: Servo/PWM Pi hat overheating and smoke

Post by buddhabandit »

I also fried the same chip on the same board (PWM servo hat , 16 channel). In that case, I was using the Android Things image (not Raspian), so not sure what happened, but didn't think board should fry from bad command sent to board. Used same power supply later with second PWM hat with Raspian and python and was able to get steppers to behave (although Hitec HS-785HB is pretty much useless to me because you cannot rely on any "home" position.)

I have another question, because I fried the DC/Stepper motor hat for the Pi today too. I read all the docs and warnings about voltages, amps, etc, but I think I blew it (literally.) . I ordered the 12v 5A power supply for the hat as recommended, but I think it was too much for my stepper motor. I guess I thought a larger voltage would be ok, but then I read today that the stepper motor has to match the supply?? Still a bit confused. Including stepper specs below:
stepperSpecs.JPG
stepperSpecs.JPG (150.08 KiB) Viewed 369 times
So for that stepper, would I just need a different power supply? When I ran the 12v power supply, the steppers behaved very strangely with the demo file, and then the board smoked. I have another one but don't want to smoke that.

Jerry

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