Probably burned...

Hello! Today I made a huge mistake :( I connected pin Gnd or Vin to 5V... This destroyed my UNO. Diodes are lighting but nothing else works. Is there any way to fix it?

replacing the atmega328 chip will hopefully make it as good as new again. It's very easy and the chips are very cheap. Make sure you buy some that come with the arduino bootloader preloaded in them, if you can't flash it in them yourself.

Thank you for your answer. Is there any way to check if chip was burned? I pulled it out and nothing changed, diodes are still lighting.

When this situalion took place i feel that the current regulator (this next to external power supply) was very hot. Maybe it is the reason maybe I connected it to pin 3.3V?

Unfortunately, i don’t have the technical knowledge to advise you how to determine if something else is burnt, but from my experience the chip is the one that usually gets burnt (been there done that :stuck_out_tongue: ) and it requires no knowledge or skill to replace. So why don’t you give it a try? When i burnt mine, everything was lighting up perfectly and looked like before, it was seen by my computer at the serial port, but it just did not do what it was supposed to and when i was trying to upload a sketch i’d get timeout errors.
A new chip after all should cost only a handful of dollars, why not try replacing it?

I bought new chip and now I am waiting for it ;)

I noticed that when I connect power to my Aruduino, an element next to power plug (see picture) are getting hot (when I connect something to 3.3V and GND pins). What is this element? Is there any way to replace it? I also have a current on the other pins.

I replaced the chip but it is still not working :( The orange diode is blinking and when I press reset button it blinks 3 times fast (but the green diode is still lighting).

That is the voltage regulator IC. First of all are you able to see the arduino in serial port?

Yes, it is visible.

try the loop back test. If it is ok,then the USB-TTL(FTDI/atmega8) chip must be alright(it is the costliest component in arduino i think, and hard to replace).

When I am doing this test RESET and GND should be still connected?
I do not know what think about this:

I can not found “Serial Monitor” program :frowning:

you can use the serial monitor of arduino itself. It can be found in the right corner of arduino IDE window(see attachment). You will have to keep GND and RST connected.

If this test is ok. Are you able to see a 5V between VCC and GND ? Can you attach a photograph of the arduino connected to your computer also?