Leonardo not recognized any more

Hello!

I am using an Arduino Leonardo and it was working properly until I connected the 12V DC to the power input.

Since then the COM port cannot be found any more an all LED's on the Arduino are on.

I read that this is the case if an external power supply is used. But if I disconnect the external power supply, the LED's are still switched on.

Does any one have an idea what could have happened?

Regards, zudy

You should be able to safely put 12V to the DC power jack and the regulator will regulate it down to 5V. This should have not blown anything.