PWM Servo Hat Overheating

[orcam]

This is re: Order Confirmation No: 1254250-4140382363, and related to 1 x Adafruit 16-Channel PWM / Servo HAT for Raspberry Pi - Mini Kit[ID:2327]

This is what happened:
- Setup and solder the pins as directed. Solder connections look good
- Connected the board to Raspberry Pi2, plugged in 5v 4A supply bought from Adafruit, and went through the tutorial. i2cdetect finds it and confirms address 0x40.
- Attached one servo to channel 0, and run Servo_Example.py. The servo didn't move. Changed the frequency setting to 100Hz, instead of 60Hz
- While trying to debug this, after 5mins or so, there was the unmistakable components burning smell. The MOSFET was extremely hot.
- Did a short check, and now +5 and GND pins show shorted, I suspect the MOSFET is burned and shorting power and ground.

I send a mail to support@ and they suggested I should post to this forum.

Thanks in advance for the help.

[adafruit_support_bill]

Please post photos showing your soldering and connections to the HAT.

[orcam]

Here are the pictures.

hat2.jpg (459.83 KiB) Viewed 611 times

hat1.jpg (666.11 KiB) Viewed 611 times

If power/ground is shorted because of soldering, it would just load the power supply, the MOSTFET would not be damaged. I think something else happened and MOSFET burned, shorting power/ground on the board.

[adafruit_support_bill]

If power/ground is shorted because of soldering, it would just load the power supply, the MOSTFET would not be damaged.

Given that all of the current flows through it, a short between V+ and ground could definitely overload the MOSFET.

When you initially plugged in the power supply did the green LED light up?

[orcam]

Yes, the green LED lighted up. Even now it lights up, but the MOSFET gets very hot in seconds.

[adafruit_support_bill]

It is not a dead-short then, since you still have a voltage drop through the led. We can try replacing the HAT. Please contact [email protected] with a link to this thread.

[Roark]

I'm having the same exact problem, was there ever a solution found, or should I email support?

[adafruit_support_bill]

@Roark - Please post photos showing your soldering and connections to the HAT.

[Roark]

The hat has been working fine for several weeks, and I haven't soldered anything new to it recently.

[adafruit_support_bill]

What are you using to power the servos?
Does the green led illuminate when you the power connected?
What servos are you using, and how many?

[Roark]

I'm using a switching ac/dc power adapter, the model number is GEO151UB-5025. The green LED does turn on, and I'm using two tower pro SG92R micro servos. Thanks for the quick replies.

[adafruit_support_bill]

Do you have any specifications for that power supply? I searched a bit and only found input specs. Nothing about the output.

[Roark]

I bought it from adafruit, here's the link: https://www.adafruit.com/product/276

[adafruit_support_bill]

And when did you purchase the PWM Servo HAT?

[Roark]

On 1/30/2016, the order ID is: 1003419-2118688374