Arduino pro mini burning out

I have trying to power a pro mini by connecting 6 volts using the raw pin for positive and the gnd pin next to the raw ping for negative. The board burns out after 30 sec. I tried again and again the second board but ed out. I have the 5v boards. Please help.


Are you sure you are using the RAW pin?

As I understand it.. on the Pro-Mini the RAW pin is the input to the on-board regulator & you can connect up to 12V to the RAW pin and VCC will remain at a constant voltage.

What EXACT pro-mini are you using? (there are many variants/clones out there)

Your either connecting the Pro Mini incorrectly or the Pro Minis are faulty.

Show us a picture of how it its wired up, thats all of the connections.

Explain what 'burns out' means exactly.

Image posting guide.

6volt on RAW/GND is fine, but what else have you connected to the ProMini.

What was the voltage on Vcc when you did this?

What boards exactly have you got? IE where did you buy them, product page....

6v in the RAW pin might be a bit low.

Suggest you try 7-9v on RAW.

As for the servo, many need 6vdc for power.

Let us say you are powering the Arduino with a 9v power supply on RAW and powering the servo with a 6v power supply.

Remember the GND on the Arduino will to be connected to the servo power supply GND.

OK, here's the Pro Mini (original, but the side pins will be identical on clones) layout:

You are powering the top right hand two pins.

You seem to be suggesting that after 30 seconds, the pilot (power) light on the Pro Mini goes out? Not the "L" (pin 13) light? And the board is unusable after that?

How have you been programming them?

Do post your code (according to the instructions).

Need to see a real picture of the setup.
Badly soldered pins (or not soldered at all) or bad breadboard/wiring are too common here.
"a 6volt supply" and "a servo" are too vague. Give facts.

Edit: Seems you don't have a capable power supply (current).

Best you provide a clear photo of all your project showing connections.
People here are trying to get more info from you and without it, no-one can really help,only take educated guess.
For example, where did the regulator come from , no mention previously.
One minute you say it doesn’t work with 6 or 12 v, then you say later that it does on 12v.
Somewhere is also a reference to using 22v, which we can only assume is a typo error.
Get the drift…?

This begins to sound as if the OP is attempting to power the servo from the 5 V output of the regulator which would be foolish indeed, Why else would he have referred to "the voltage across the regulator" and "Not enough to drive my servo"?

If the servo is powered from the exact same 6 V which fed to "Vin", then the regulator could not be overloaded.

Does the board burn out as in "won't work ever again" or "will work after restart"? There's no mention of replacing the board, just trying new things. Sounds indeed like an inadequate power supply - overheating or going into overload protection after having to power that servo for half a minute and shutting down.
What exact power supply?
What exact servo?
Where's the a complete schematic of your setup?

It should run just fine on 6V, unless yours has an odd regulator that just won't work when it thinks the available dropout is too low..

If that 6V is well regulated (a battery can give a lot more than nominal, depending on the type) you can use two diodes in series and then power your Pro Mini through the 5V pin, using the diode drop instead of a regulator.

We still have no clear idea of what rayluc is connecting to what!

I am sure the problem is there somewhere!

I mean:

Yes I get it. 6 volts is not enough. 22 volts works. For the FCC pin I am o Lynn maestri g about 3 volts. That does seem right.

Really? :cold_sweat:

To drop the voltage, as mentioned, you can take your 6V battery and add a Silicon diode (@0.6V) and a Schottky diode (@0.3V) in series with the battery.

Feed this voltage into the 5v pin on your Arduino.

6V - (0.6V + 0.3V) ~= 5.1V

Make sure you use diodes of the proper rating. 1N4007 and MBR160RLG.

This should be good for about 0.5 to 0.75 amps.

I switched out the 4 AA batteries with a 12 volt sealed battery used in depth finders and other electronics.

Now that can potentially burn out your ProMini in a spectacular way.

Anything else connected to that ProMini?

That's exactly the point - so you can then power your Pro Mini straight to the 5V pin, instead of through the Vin pin and the regulator.

I guess I am not getting it. If 6 volts doesnt light up the board how does putting diodes in series help? Foesnt it drop the voltage even more?

Do not put the 6v into the ‘RAW’ (Vin) pin.

Put the 6v (with the two diodes) into the ‘Vcc’ (5V) pin.

Please don’t advise that.

The ProMini has a tiny 5-pin 150mA voltage regulator with a dropout voltage <=0.1volt.
Perfectly ok to power it with 6volt on V-in-raw.

It seems that that 6volt supply is collapsing under the 1.2Amp stall current of the MG995 servo, that is also connected to that supply.
Diodes > 5volt pin will only make it worse.

OP, get a decent 6volt supply that an deliver at least 1.5Amp.
Alkaline AA might work for some time, plain AA or AAA batteries most likely not.