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Topic: Magic smoke with Lolin D32 pro (Read 352 times) previous topic - next topic



Before we carry on, could you please clarify:

1. You connected the 5V power supply, which is intended to power the servos, to the lolin 3.3V pin


2. You connected the 3.3V pin on the lolin to the servo trying to supply power to it?

We seem to have different initial interpretations - I now also tend to guess it will be 2 above.

Yep. Case 2. I connect the servo to 3.3 and in less than 5s, the smoke out


Nov 12, 2019, 12:21 pm Last Edit: Nov 12, 2019, 12:24 pm by Willem43
OK.  @MrMark was correct and I was wrong.

USB should have only supplied 500mA, it possible that is exceeded that - who knows.  My first guess would be that the the regulator is blown - it can only supply absolute max 600mA and a servo most likely starts higher than that.

How good are you at soldering/unsoldering?  I would have started by removing the regulator and then measure and check other things.  It is difficult to check the other components if the regulator, for instance, is shorted.

Looking at your picture in post #7, the group of components between the gold plated hole and the ESP, above the white connector, belong to the power block in the diagram.  (The 5 pin chip next to the battery connector is for charging it).

The large (all relatively spoken) unit just above the white connector (marked SL) is, I would say, the diode we are talking about.  The side away from the white bar, to the left, should be close to 5V (it is directly connected to the USB 5V).  The bar end should be about 4.5 - that is obviously if everything is working.  The three pin device will be the FET supplying power from the battery, when the USB is unplugged.

If you do not see 5V on the non-bar side you are not getting 5V from the USB - maybe due to excessive current drawn - hence the reason I would remove the regulator.

It is, for me, easy to remove a component like that using a good de-solder braid,  Just as easy to put back.  YMMV.

NB: Does anything actually look a bit charred in any way - if you had smoke and got a stink, something burned.



Thanks Willem and Mark, I guess its better to buy a new one and i should never use any power pin on esp board for any purpose anymore - an external power board will be a good choice for not encountering any mistake again

But anyway, im still feel angry a bit for this time, 15$ has gone -_-


If you are not into building electronic circuits you are better of by taking the route of least resistance.  Probably the best decision.

The way to power servos, I use a lot of them in my model railroad, is to power them with an external power supply capable of providing the required current.  The arduino boards (and obviously even worse, ESP, due to their 3.3V) are not up to powering servos.

Good luck and have fun.


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