# Mega 1280 power supply issue

**URL:** <https://forum.arduino.cc/t/mega-1280-power-supply-issue/70346>\
**Category:** IDE 1.x\
**Created:** [August 31, 2011, 7:44am UTC](https://forum.arduino.cc/t/mega-1280-power-supply-issue/70346 "2011-08-31T07:44:48Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [August 31, 2011, 7:44am UTC](https://forum.arduino.cc/t/mega-1280-power-supply-issue/70346/1 "2011-08-31T07:44:48Z")

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Hi hope you can help  
I will be running my 1280 board using a 9 volt power supply connected to Vin. I note that the 1280 will also draw power from the USB port when it is connected. My question is - will I damage anything if my 9V is connected at the same time as the USB is plugged in?

Thanks  
Bryan

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [August 31, 2011, 8:12am UTC](https://forum.arduino.cc/t/mega-1280-power-supply-issue/70346/2 "2011-08-31T08:12:22Z")

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hi blt!

no, you will not damage your arduino or pc. in some cases, you must connect both, power and usb. ie. if you want tho programm or debug the board and have a lot of load on the board installed witch will exceed the maximum power-rating of an usb-port.

lg oxyl

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<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [May 5, 2021, 3:50pm UTC](https://forum.arduino.cc/t/mega-1280-power-supply-issue/70346/3 "2021-05-05T15:50:21Z")

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