I was connecting L293d Motor Driver IC with an Arduino Due Board. May be due to wrong connections, but when I made the grounds common, the Arduino LED goes off and Atmel IC heats up. When I reconnect my Due board with my PC anytime, the LED turns on and slowly dims to off and Atmel IC fries up.

I wanted to repair it. What should I do?

I have checked the input voltage of the AMS1117 3.3V regular IC as 3.8 V, while the output is 2.2 V. If I externally give 5 volt at input again, the input voltages drops. The regulator is loading.

I thought of replacing the regular IC? Will that work?

Also I externally powered the Board with 3.3V by its pin labeled "3.3V" . The LEDs glow on and did not go off. But the Atmel Microcontroller IC becomes very hot.

What should I do?


1 Answer 1


Motor driver boards exist to allow an MCU to control a motor without having to supply its power. If you try to power motors from the Arduino as well, they draw too much current and things get hot or damaged.

The 3.3v pin is only for supplying modest amounts of current at 3.3v from a 5v Arduino. You can not back-power the board with it. I don't know what happens if you try, but I bet it isn't good...

  • Supplying 3.3V to the board and trying to draw from the 5V connection will damage the voltage regulator. Since the ATmega16U2 on the board draws from 5V, well... Aug 26, 2016 at 21:23
  • I have disconnected the motor driver and when i give USB power. Led glows for short period of time and then turns off. At the same time MCU heats up. and i am unable to upload any code in it. Does changing a regular will fix it up? Aug 28, 2016 at 8:57
  • @MasoodSalik MCU heating up without anything connected to outputs means it's more or less destroyed. Something reached break down voltage and now it's permanently conductive.
    – KIIV
    Aug 28, 2016 at 9:40

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