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Topic: Fried MEGA replacing the 2560 (Read 159 times) previous topic - next topic

kyuzumaki

I think I fried my Mega when I connected an ESC that was outputting 6.5v from the BEC instead of the rated 5V. Some smoke came from the processor and it got hot.

Now when I plug it in no com ports appear the L, TX and RX lights all come on solid.


I have two questions that I haven't been able to answer from my searching.

1: Is there a way of testing the chip to make sure its dead?

2: If I buy a new replacement processor and manage to solder it in there how do I write the boot loader?

sarouje

You can bootload the processor using a USBASP or another Arduino Uno as ISP.
Sony Arouje
http://sonyarouje.com

Budvar10

If COM port problem then ATmega16U2 could be also damaged (on original Mega) or generally USB/serial chip.

1.The way of testing is mot so easy. One thing is if it is starting and if it is able to program it. The second is if the ports are working properly. You have to test each one.

2. As @sarouje wrote you can bootload via ISP. Both MCUs have a 6 pin ISP connector for that purpose.

Consider if it worth for effort. You can learn something of course, but the price of 2560 (cca 9EUR) - one of the most expensive ATmega, soldering... The price of the new original Arduino is very close.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

mrburnette

Yea, budbar10 it the answer ... "The price of the new original Arduino is very close."  Unless you have a hot-air rework station, my suggestion is to just forget about replacing the 2560 uC.  Clone boards are not expensive.

Now, after you replace the smoke'd Mega, you may wish to see if the old one can be repaired by using desoldering-wick and a pencil iron and lots of patience.  But first, you need to test the old board and determine if the 16U2 is defective ... several ways come to mind, but a loop-back is likely the best approach if the voltage regulator and diode are still functioning... use a DVM to test.


Ray

Budvar10

Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

mrburnette

:smiley-twist:  I am budvar10.
OMG!  ... as I once would have said while in Japan, "gomenasai"

... but when you get down to it, budbar has some interesting connotations:

Budvar10

My nick is according my favourite Czech beer.  :)


Sorry for OT.
Arduino clone with ATmega1284P   http://forum.arduino.cc/index.php?topic=277260.0

CrossRoads

Is the 2560 hot to the touch when the board is properly powered? If yes, it is shot.
Same with the 16U2.
I was making this board with the idea that it could be used as a plug in processor on a Megaboard, but haven't done the mating board yet.
http://www.crossroadsfencing.com/BobuinoRev17/


Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

avr_fred

My experience with trying to remove smd ic's with solder wick has been mixed. Board quality and pad thickness play a large role in being able to remove the package without damage to the pads.

When I know the ic is dead and there no chance of reuse, my method for dealing with packages like the 2560 is to attack them with my battery powered (small!) Dremel tool with a new, thin resin cut-off wheel. I carefully cut all the leads where they enter the package, being careful not to touch the board. It's not that difficult and the bigger and thicker the ic, the easier it is.

Once the package body is out of the way, it is a very simple matter to place the board on edge and work from top to bottom of a row of leads, apply solder and run down the row, removing all the pins in what becomes a big blob with gravity easing the task considerably. Rotate the board 90 degrees and repeat the process until all the leads are removed. Then it is time for the solder wick to remove the remaining solder on the pads and you're now ready for the new chip. It is fast and the chance of damage to the board is much lower, so long as you have a study hand and good eyesight when cutting with the Dremel.

CrossRoads

If one has a hot air work station, then taking SMDs off is not hard. I bought a variety of nozzles for the chips I used, they are used to direct hot air to all pins at once, letting a chip be removed in one fell swoop.
I believe this one for a Mega, 15mm spacing for the 2560s 14mmx14mm body.
30 seconds of hot air and the part can be lifted up.
http://www.mpja.com/Rework-Station-SMD-Nozzle-15-X-15mm/productinfo/16124+TL
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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