I hope I didn't kill it :0

Development Tools IDE 1.x
1

Ok, so I was playing around making a boost converter. Not important right now. Pleas help me solve this mystery.

Something in my arduino uno r3 went terribly wrong. Here's a list of faults:

  1. pin 13 does not work, at all. It's at around 0.4V, no matter what I set it to

  2. the yellow LED at pin 13 is always on. Same problem, no matter what I do, it's on

  3. the dual op-amp LM358D gets insanely hot, after about 5 seconds it's too hot to touch. Even with a blank arduino sketch, and all the pins unconnected, this op-amp is on fire

  4. the reset button does not work, I click it, nothing happens

All the other digital pins seem to work fine (although I'm getting about 4.3V instead of 5 for digital high) , I can upload sketches, all that good stuff.

I did some measuring, here are some weird things I found:

a) multimeter says that on the LM358D op-amp pin 5 (Vcc) and pin 6 (GND) are shorted

b) there is a 1Kohm 8 pin resistor pack next to the yellow led at pin13. The upper rightmost pin is shorted with the bottom middle 2 pins (I don't know if this is done on purpose - I can see a path between the bottom 2 pins, so those two are shortes by design I guess)

c) if I remove the microcontroller and power the arduino via external 12V power, the op-amp still gets hot hot hot

What do you guys think? Did I kill it? Is it the microcontroller? Could it be the op-amp has died? Could it be the resistor shorted out and now I have massive current flow through the yellow diode.

2

Opamp is trashed, all outputs are shorted to ground, and this is what's keeping pin 13 low and the LED lit.

The chip may be trashed by now if you've been trying to drive pin 13 high (since you'll have been exceeding the current limit spec).

The opamp is the first thing to go when you abuse the power system. Did you connect the power supply backwards to the barrel jack? (be glad it wasn't plugged in, if so - then you'd have taken out the serial adapter too).

3

It was powered via usb. I don't know what exactly fried it. But working with inductors I'm not that surprised.

Can I still use it though? I mean all the other pins work, kinda.

Also what about the weird shorted resistors?
Also it's a dual op-amp package, is there a possible way that only the one op-amp died, and the other one is still ok?

4

Both opamps are probably bad, that's usually what happens (often it's caused by a bad power supply on the barrel jack). Replace the 358 before continuing to power the board to prevent further damage.