replace arduino mega chip

Today i killed my arduino [edit]arduino Mega[/edit]… Don’t know exactly what happened but i think it had something to do with 24v and a loose wire.

The symptoms;
With nothing attached, the moment i plug in the usb cable the chip itself heats up quickly.
The computer does create a com port.
5V pin gives 4.1V (usb voltage 4.85V)
pwr led comes on
rx and tx leds blink a couple of times

With only an external 12V power supply the chip heats up as well.
5V pin gives 4.97V
power led comes on
rx and tx leds blink once

quick diagnose;
Dead atmega chip but regulator and ftdi chip are ok

The question;
Is there anyone (preferably in The Netherlands) that is capable/willing to replace the chip?

Jeroen

Do you need a ATMEGA328 for a Duemilanove or an ATMEGA1280 for an Arduino Mega board?

Replacing a 328 on a Duemilanove is not that hard ;). Just get a bootloaded 328 from eBay or something.

ATMEGA1280… sorry i wasn’t clear.

I have no problems with soldering throughole and the larger surface mounted parts but i do not feel confident to solder a ?10-15 ATMEGA1280.

Jeroen

edit: programming the bootloader will not be a problem as i have a stk500 board from atmel with various programming options.

edit 2: the arduino draws 700mA at 12V. Strange there isn’t any smoke coming out… :-?

ATMEGA and Arduino Mega is a bit confusing, not your fault. I asked just to be clear ;).

I just took a look at my Arduino Mega, seems like a really hard task to replace the ATMEGA1280. I hope you will find someone who can do that for you :).

You might want to try http://www.circuitsonline.net/forum/. That’s the biggest electronics forum in The Netherlands. Maybe someone there has the knowledge to replace the chip for you. Tweakers.net also has an electronics forum but I think requesting things like that is not allowed there (maybe in the “EL kroeg topic”).

Good luck! :slight_smile:

Btw; where did you get the atmega1280 for just ?10-15? It’s ?23.24 at Farnell (excluding VAT).

http://nl.mouser.com/search/ProductDetail.aspx?qs=2nyfZ6BV3ogEHzLMx/XdoQ==

Was one of the first hits on google when i wanted to know an estimate.

Jeroen

Thanks for the link btw. :slight_smile:

Mouser charges ?20 shipping costs on orders below ?75. The ATMEGA1280 is on backorder, if I click on delivery times it seems like it’s going to take more then 2 months to get one. It might be cheaper and faster to buy a new Arduino Mega ;).

http://cgi.ebay.nl/Arduino-MEGA-ATMEGA1280-Broad-USB-cable-/290459877373?cmd=ViewItem&pt=LH_DefaultDomain_3&hash=item43a0c1fffd

Thanks for the advice/info. I will probably get a new one and some barebone atmega328’s to zap.

Do you have experience with those sellers?

Jeroen

No experience with both sellers, I just searched for the cheapest Arduino Mega on eBay ;).

Not sure about the quality of those boards. If you are looking for a really good clone I can recommend the DFRDuino Mega, really good build quality.

I found a replacement processor. ?16,00 and up to 2 weeks waiting. From a store in Dordrecht (The Netherlands)
Also bought solder-wick and a new solder-tip. Will practice soldering smt components on old motherboards first.

Also ordered a Duemilanove online and that one should be in tomorrow.

The positive effect of being without an arduino is that i finally arduino-ized my asuro robot.

Jeroen

Also bought solder-wick and a new solder-tip. Will practice soldering smt components on old motherboards first.

To do a 1280 is going to take more than just solder-wick, solder, and a solder tip. You are going to want flux - a LOT of flux. When doing SMT work, lots of flux is paramount, from what I understand.

Look into “horizontal drag” and “vertical drag” rework techniques; there’s quite a few videos on youtube about the process. You’ll want really good paste solder, and lots of liquid flux - neither of which, for the good stuff, will be cheap. There’s also certain kinds/shapes of tips for the iron you’ll need.

You’re also going to need practice - a lot of practice. If you want to do this right, you’ll learn a lot and probably be able to solder anything afterward - but you’ll probably also find that you will have spent more on the learning than if you had just bought a new Mega. So keep that in mind: Are you in this to repair your Mega, or are you in this to learn SMT rework?

Good luck, and let us know how it turns out, regardless!

:slight_smile:

I’ve soldered things (in the broadest sense) for years but this will be definitely the smallest/most cramped part up to now. The goal is basically to revive the already modded arduino mega. The ‘learning SMT rework’ is just for fun.

First thing will be google for a few day, then destroying some old motherboards. Then i will decide if i will do it by myself or look for someone else.

Thanks for the tip on flux.

Jeroen.

This might also be an option:

http://www.seattlerobotics.org/encoder/200006/oven_art.htm

Succes ermee!

Dank je, zal 't nodig hebben. :slight_smile:

Jeroen

I’ve replaced chips on this scale before, it’s do-able but not easy, you have to wonder for the cost and effort is it worth it?
There are so many other things that could have been fried, smt resistors or even the pcb traces, i’ve not looked that closely at my Mega board to see how many layers it have but it’s a pain when one of the hidden layers gets fried.
anyway, desoldering the Mega1280 is easy, as with all smt reworking i do i just flood all the pins with solder and use the iron to heat each side quick then just pick the chip off the board with fine tweezers.