How to find broken arduino uno component(s)?

Development Tools IDE 1.x
1

Hello everyone,

A few days ago I was bussy with an h-bridge circuit when my uno R3 started to heat up. I must have accidentally switched gnd and vin on my power source, or I shorted them. Now when I connect the arduino with usb to my pc it doesn't get recognised.

In the attachment I marked which component heats up when arduino is powered on. How can I figure out what that is and if anything else is broken?

Thanks in advance,

Dytek

Sketch226125255.png

2

(deleted)

3

Thanks,
but I looked at the schematics of the uno and I've got no clue at what they mean...

4

That chip is the LM358 comparator.

Try the loopback test also.

Is the '328P getting warm/hot also? That's a good indication it is damaged.

5

Okay, I powered up the arduino again and the only thing heating up (it's extremely hot and starts to stink after a few minutes) is the LM358 comparator, it seems like the 328P doesn't heat up. Does that automatically mean that the 328p is undamaged? And how easy/difficult would it be to replace the comparator?

The loopback test doesn't work because the arduino doesn't get recognised as a device by the computer, I tried on two different pc's to check. What does this mean for my arduino?

Thanks

6

How good are your small component rework skills? I have the tools (hot air rework station, soldering iron with very small tip) to do it. Without similar, it can be quite difficult, especially to put a new one back on.
Do you measure 3.3V & 5V at the power header?

7

My small component rework skills are basically non - existent and I don't have those types of tools (I might invest in them though). I measured the 5V and 3.3V pins, they gave 3.9V and 3.3V respectively. Is getting 3.9V from the 5V power header normal?

8

No. 3.9 indicates something is dragging down the 5V source, likely chip that is overheating.
You're kinda dead in the water with that board until you can remove the chip.

9

Okay thanks a lot, I'll see if I can manage to replace the chip, then I'll see if my arduino works again and report back.

10

Thanks a lot for your help, but I decided to buy a new arduino uno. The tools are just too expensive for me as I would hardly use them after replacing the chip.