Uno broken because of a link between pins 10 and 11?

Official Hardware UNO Family UNO R3
1

Hello,

I have broken a Uno board (very hot + a little smoke) but I don't know why. The board was working well during some days, then, without doing any change, it doesn't work anymore. It is not recognized by the Windows device manager.

I use the Motor Shield v3 with an external power (about 15V) and I cut the Vin jumper. As I previously used a Uno Wifi Rev2 board, the pins 10 and 11 were linked as recommended (UNO WiFi Rev2 and Motor Shield Rev3 compatibility).

I used this configuration during many weeks with the Uno Wifi Rev2 board without any trouble until the board was not recognized anymore (without smoke). So, I replaced it by a simple Uno, but I forgot to remove the link between pins 10 and 11.

So, I have some doubts about 2 points:

  • Does a link between pins 10 and 11 may damage a Uno Wifi Rev2 or a Uno boards?
  • Is the Vin jumper fully cut? It seems it is, but I have to seriously check it ... But that was working normally during a long time.

So, do you think that a link between pins 10 and 11 can be the cause of the damage?

2

if pins are output and one is HIGH and the other is LOW, you create a perfect short that will likely damage de pins / board.

3

But as recommended in the above link, we have to create the link. How to avoid a short if we have to use them with output LOW, HIGH, ...?

4

You only need the link on the UNO Wifi Rev2, not an UNO, because the UNO WIfi Rev2 does not have PWM on pin 11. If you are actually linking pins 10 and 11 together, then pin 11 must always be set to INPUT. A better solution is to modify the motor shield to break the connection to pin 11 and instead wire it to pin 10.

5

Ok, I understand that there was no problem with the Uno Wifi Rev2. And very probably, with the Uno, this is the cause of the breakdown. True?

Is it normal that I was able to run the same sketch during some days with the short? And, suddenly without any change, the board becomes damaged.

6

I have moved your Topic to Hardware ....Please try not to post in Uncategorized again, If you are unsure about the categories refer to this guide or to the stickies for each category.

Thank You.

7

It is a possible cause of the problem. Without knowing anything about the code you are running, or if you have anything else connected in addition to the motor shield, it is impossible to tell.

8

That means that the serial-to-usb converter is damaged; on an official Arduino it's a 16U2). I do not think that just a short between pins 10 and 11 can cause that.

What is getting very hot? The serial-to-usb converter or the 328P? Or something else?

9

It's difficult to know exactly what was getting hot. The smoke came from the power port. And the whole board was hot.

I have to say that another board, a Uno Wifi Rev2, was broken previously, without smoke or high temperature. The difference between these cases appeared in the device manager. The Uno appears in the COM ports section. The Wifi Rev2 appeared as "ATm32U4DFU" in the Other devices section (No driver found for ATm32U4DFU / Uno Wifi Rev2 - #5 by ptillisch).

10

I'm at a loss.

In the first paragraph of the opening post you state that your Uno is not recognised.

Now you state that it's recognised.

11

Sorry, I was not clear. The Uno appears in the Ports section but grayed. The Wifi rev2 didn't appear in this section, only in Other devices.

12

And it disappears when you disconnect the board?

I've never seen that. Do you have "show hidden devices" enabled in Windows device manager? In that case, the icon in front of the board will be greyed out (Windows 10) but the text will still be normal.

If so, disable it and let us know if the Uno still shows in device manager.

13

Sorry again! After the breakdown, the Uno always appeared as grayed if it was connected or disconnected because the option "show hidden devices" is enabled. Without this option, it didn't appear. I say "did" because I returned the board.

14

As I said previously, I use the motor shield V3 and I cut the Vin jumper. I was not sure that it was cut, so I tested the continuity with a multimeter between the 2 small pads of the Vin jumper. I get a bip. So that means that there is a continuity and the jumper is not fully cut.

I cut again and again and get a stripe on the board between the pads. So, that should mean that the jumper is cut. But it isn't, I still get a bip.

So, how to remove the Vin jumper? It's a pity that the motor shield doesn't include a switch instead of a jumper to cut. I believe that other motor shields include a switch.