duet arm chip replace

Guys i have a couple of broken duets in my hands . And i was wondering is it possible to have replaced the arm processor ? Does it need programming before attaching to the board. In my simple mind i though that the programming is the firmware itself, isn't it ?

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Delta Printer
Duet 0.8.5 firmware 1.19

No, it doesn't need programming first.

I have tried to replace the chips on 2 boards, both without success. There are two issues:

1. Removing the existing processor without lifting any traces. I got both chips off by heating them with hot air from the top, but some traces lifted.

2. Soldering the new chip on the board so that it seats all the way around, without overheating the chip.

I think my next attempt will use a jig to hold the board level, a thermocouple stuck to the top of the board near the chip to monitor the temperature, and hot air heating the board from underneath in the vicinity of the chip. Maybe also epoxy a wire or small dowel to the centre of the top of the chip, so that it can be lifted off cleanly when the thermocouple indicates a suitable temperature has been reached.

Make sure you have a no-clean flux pen to wipe on the pads before fitting the new chip.

Edited 3 time(s). Last edit at 06/05/2016 12:11PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

... I'm desoldering SMD-chips "pinwise" with pushing a thin (50 microns) Nickel sheet under the hot pin, so it cuts the solder and the pin stays free ... nickel, als it won't bind to the solder itself.

Then again resoldering the new chip pinwise too with a fine soldertip and the thinnest available solder with 0.3mm diameter without problems ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

A standard hot air rework station will do the job just fine and whilst I haven't removed those specific arm chips I have pulled similar sized microchip processors from boards.

Solid trick is to run a bead of smd solder flux over/around all the pins prior to hitting with the hot air and have a smd suction device to lift the chip away.... The flux will give a very accurate indication when you have reached the correct temp, hard to explain, easy to see.

Sometimes for pcbs with heavy copper or good heat sinking you need to preheat the entire board being careful about max temps for all components.

Thanks guys for the inputs. I have the board to a local electronic service spot and they told me to through it at the garbage. On the other hand i know that it is a simple procedure for an electronic repairman and even easier if there is a preheater available. Anyway my knowledge at the electronics lack ( as anywhere else ) but i ll look further to find someone here in greece that can import the arm and also replace it on the board.

Vdx i am not sure i understood how you cut the legs but it's sound a brilliant idea.

Except mouser do you know any other online shop that i can find this chip?

Also when i ll install it then the only thing i ll need will be a firmware install ?

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Delta Printer
Duet 0.8.5 firmware 1.19

Quote
Gaou
Vdx i am not sure i understood how you cut the legs but it's sound a brilliant idea.

... I'm using thin stripes of 50 micron thick Nickel foil (to find in "radio-tags", used for anti-theft on DVD-covers) and push them under the pad while melting the solder, so the foil separates the pin from the pad.

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Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Farnell and RS Components both sell the atsam3x8e-au.

If you replace it successfully, you just need to install firmware using bossac. The bootloader is built in to the chip.

Edited 1 time(s). Last edit at 06/06/2016 04:47AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Removing chips without special equipment is really easy with ChipQuik. It's a low-temp alloy, so you don't overheat the board.

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