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Topic: Urgently , my arduino Uno board can't reset ! and get hot !! (Read 239 times) previous topic - next topic

Abdelrhman_Safwat

Sep 08, 2017, 03:45 pm Last Edit: Sep 08, 2017, 04:04 pm by Abdelrhman_Safwat Reason: Adding pic
Suddenly my arduino board can't reset when i press reset button many times , also  i found it gets too hot from that part besides the crystal .. i removed the microcontroller and try to power the board and found the same part getting hot !! plz help me quickly :( i can't understand why

sterretje

Which part?

In your picture,

The part above the xtal is the 16U2 micro responsible for the communication with the PC. The one underneath the xtal is the LM358; it drives the LED and it is responsible for the detection of 12V on the Vin pin or the barrel.

The part hidden by your pointer finger is the 3.3V regulator and the part next (above) to the barrel is the 5V regulator.
If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

Abdelrhman_Safwat

#2
Sep 08, 2017, 08:32 pm Last Edit: Sep 08, 2017, 08:37 pm by Abdelrhman_Safwat
Which part?

In your picture,

The part above the xtal is the 16U2 micro responsible for the communication with the PC. The one underneath the xtal is the LM358; it drives the LED and it is responsible for the detection of 12V on the Vin pin or the barrel.

The part hidden by your pointer finger is the 3.3V regulator and the part next (above) to the barrel is the 5V regulator.
Thanks brother for your reply i have updated the pic you can check it for me plz , i appreciate your help ...  this part gets too hot whatever i connected the arduino to the PC or connect it through a power Source , Also in the same time it doesn't response to the reset button , in the other hand i can upload any sketch normally !

Thank you in advance

sterretje

If I was inclined to repair it, my attempt would be to

remove the FET (right of the golden part (fuse) on the left).
if that solves the problem, replace it
else
remove the IC that gets hot

Disadvantages
Without the FET, you can't use USB to power the Uno
Without the IC, on-board pin 13 led will no longer work.
If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

Abdelrhman_Safwat

If I was inclined to repair it, my attempt would be to

remove the FET (right of the golden part (fuse) on the left).
if that solves the problem, replace it
else
remove the IC that gets hot

Disadvantages
Without the FET, you can't use USB to power the Uno
Without the IC, on-board pin 13 led will no longer work.
I will try and tell you the results .. Thanks

Abdelrhman_Safwat

actually i have tried to observe the behavior of the arduino , So i fixed a large PC fan over the Arduino to get rid off this heat so it can't damage it . And powered it and found besides i can upload sketches very normally  :

+ Reset button in fact works ! and i placed a led over pin 13 to ensure this and tried many times .
+ only the Led having the letter (L) always on , and didn't blink with the blink sketch example but in the same time the led which i attached to the pin 13 did


Do you advise me the same you have advised me before ?

sterretje

Just replace the IC and try. If it's still gets hot, there is more wrong.

My previous advise was based on the assumption that most likely cause was that  you probably blew the fet using a 12V power source.
If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

DrAzzy

I couldn't say whether he blew the FET, but it sounds like he blew the opamp for sure. That isn't surprising - the opamp is one of the first things to go when you abuse the external power input (that, and the 16u2 on boards that use a 16u2).
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http://drazzy.com/package_drazzy.com_index.json
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