Apparently burnt an Arduino BT - URGENT HELP

Hello all,

I am working on my MSc final project with an Arduino BT.

To do so, I was using a set of 2 AA regular rechargeable batteries to power it through the grey socket. Although the board was powering on alright, it was working very very unstable. Very hard to get it connected to the computer and upload sketches (yes, I know I have to pair it and then press the board’s reset button to upload things :).

At the lab, 5V DC to the board made it work better, so while at home I powered the board with 9V, but not through the grey socket, directly to the pin sockets marked 9V. I am sure I have not reversed polarity, but as soon as I put it in, a little smoke came out. I could not spot from which component it was, but now, unsurprisingly, the board will not turn on (LEDs will not light up).

I would hate to have to buy another board as they are very expensive in the UK and I am, ahem, a student, so is there anything I can try to measure to perhaps replace any component? The smaller capacitor beside the grey socket is working fine.

Many thanks,

Cass Surek
cass@surek.co.uk

Take it back to the lab and try the 5V. Are you sure that your 9V supply was DC and not AC? Also depending on the type you can get over 12V from a so called 9V supply.

However smoke is never good and almost always signals the death of electronics. :-[

Thank you for the reply.

Take it back to the lab and try the 5V. After this incident, I have tried to feed 2.5 V to it with the same batteries that were being used before, but it did not light LEDs anymore. I guess taking it to the lab for 5V would be the same as these , unless you tell me otherwise.

Are you sure that your 9V supply was DC and not AC? Yes, It was a 9V energizer battery, thus definitely DC.

Also depending on the type you can get over 12V from a so called 9V supply. I had measured it with my multimeter prior to using: 9.08 V from it.

However smoke is never good and almost always signals the death of electronics. :-[ That is a very nice way to put it

I ended up removing the DC-DC converter, the MAX1676 and wiring the batteries straight to the 5V pin socket. Worked beautifully and I do not have to spend another £ 70 on a new board. Yay! :)

yes that is what I was going to suggest- replace/remove the MAX regulator chip. I had a couple students who fried BT's this way- and there was a little puff of smoke in both cases.