did I destroy my arduino mega and ramps 1.4?

I was using an arduino mega and ramps 1.4 motor controller for my 3d printer.During the time of testing ,i switched the power polarities in the ramps 1.4 , then I put 12V in the arduino then the mega chip got hot.

This is the state now,when i plug the mega on to my computer :

1)The red ON led lights up and the L lights up.
2)device not detected.
3)Reset button does not make any change.
4)RX-TX  lighting up.

when i plug the 12 in the ramps:
1) the red ON led lights up, the green doesn't
I want to know if this arduino and the ramps 1.4 can ever be used again.

please help!!

thanks in advance!!

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-max-2 years ago

Do any semiconductor devices overheat on the RAMPS when powered properly, I would expect that to be made a bit more versatile with a voltage regulator, that may have failed. The red light is probably just an LED wired directly to the power rail with a resistor in series. If the chips are cool to the touch, and take 5V nominal, measure the power pins directly, and see if there is voltage across them That should be easy to do with DIP components.

If it is some horrible BGA like thing, (which I really doubt since it is a motor driver, where power and current are probably not like CPUs or RAM w/ really high pin counts) than it may be easier to find the voltage regulator, if there is one, and measure the voltage. Should be easy to spot, since it will be close to some electrolytic or tantalum capacitors, and maybe a choke or inductor/transformer and the fact that it is high power stuff vs signals is quite obvious usually. (like big fat, short traces, and ground pains, lots of via stitching, that type of stuff)

joee1 (author) 2 years ago

max!! Yeah the chips got warm when I powered it correctly!! I will try to desolder it !! thank you so much dude for your help!!

Thanks steve!!

Personally, I'd use a hot-air gun, one of the little butane ones works really well. Ideally, get a "flux pen" first, to help the solder melt cleanly. LIFT the chip off the board when the solder melts, apply more flux, wipe the remaining solder off with desolder braid.

joee1 (author)  steveastrouk2 years ago
Nice idea steve!! That is cool!!! I liked it!! I wanna try it!!! Cheers!!

Just be careful to make SURE everything is melted, because you can pull the tracks right off the board if you get too eager - and then its game over.

-max-2 years ago

Oops! well, sounds like you screwed the pooch on it. :( Does the chip get excessively warm when powered correctly? If so, then get a replacement chip, you will get some wonderful practice desoldering and soldering the TQFP package! Cheaper than a new arduino, if you can source the ATmega2560, or whatever the chip is.

Was the -12V applied across the regulated input of the arduino? You may have got lucky and the voltage regulator saved your circuit, as it did when I screwed up my multiwii FC. I was able to get it to work fine again by changing out a shunt resistor. (until I went to test it to prove it was working, until I really screwed up and had 12V across the 5V rail directly, bypassing the damn regulator [facepalm!!!])

To desolder it, you can bend copper wire into a square shape to fit snug on the all the pins simultaneously and wrap one end of it around the aron tip, after the copper square gets really nice and hot, place it over all the pins of the chip, bet a buttload of solder onto it, and once it all reflows, drag it off. Be careful not to damage the traces underneath. You can also use a razor blade and slice the chip clean off, and do it that way. Just be careful not to damage the board.

Hot chip = dead chip.

Its REPAIRable, but dead right now. You burned it out when the ramps was over-voltaged. The ramps is dead too.