Duet 0.6 suddenly can't connect, burned component

So I was just trying out new filament as my extruder started skipping, I thought maybe it overheated because it was very hot today. So I let it cool down and added a fan. After starting the duet again I am unable to connect to it. Pings return with host not reachable, if I connect via USB it gets recognized as bossac input device, but only without the SD card put into the duet. It won't get recognized if I start it with SD card. If I connect it without SD card and try to connect with pronterface it gives me an infinite loop of "[Error 22] The device does not recognize the command".

So I uploaded a picture with the components looking burned somehow (red marked):

[imgur.com]

So, what could the issue be and am I able to repair it?

From your photo, I don't think the components in the red area are burned.I suspect that you have an early Duet 0.6 on which two resistors in that area were initially fitted incorrectly and had to be reworked by hand.

I find it odd that connecting the SD card affects whether the port appears. Perhaps the SD card is faulty and shorting out the processor pins. Or perhaps the 3.3V supply to the SD card is no longer present.

With the SD card removed, are you able to upload firmware using bossac? If yes, are you then able to connect Pronterface afterwards?

Is the SAM chip getting hot?

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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].

What I forgot to mention is that it only gets recognized with 12v on. If I connect it via USB without 12v nothing happens.
With SD card inserted I get unknown device, and without SD card it's either hit or miss. I have to start it with 12v first, wait a few seconds and then plug in the USB cable. Sometimes it works, sometimes don't.

Trying to flash with bossac it connected but first threw the error "Flash page is locked". So I tried holding erase & reset a few seconds, after that I successfully flashed the firmware. Trying to connect with pronterface immediately after flashing resulted in being stuck in "Connecting...".
So I turned the duet off and waited a few seconds, turned it on and tried again: "Serial error: could not open port COM10: [Error 5] Access denied". Any other attempt to connect via pronterface resulted again in being stuck in "Connecting..."

And yes, the SAM chip is getting painfully hot. Even after only a short while. I also guess that pronterface is only stuck in "Connecting..." because it's too hot.

/E: It is now recognized as bossac input device even with the SD card, and It's connecting every time I plug it in. So no hit or miss, but still only with 12v

Edited 4 time(s). Last edit at 08/25/2016 09:03PM by Dawgon.

If the SAM is getting hot then it probably needs to be replaced, which is no an easy operation.

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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].

So I can throw the 2 months old duet away? Funny how my cheap chinese ramps combo is still working fine. Damn that's really frustrating.

Where did you get your Duet 0.6 from? If it was new 2 months ago then I would expect it to be under warranty.

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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 bought it from think3dprint3d. Already sent them a mail and they asked me to send it in. So I will do that as soon as possible and hope for the best.

My few dealings with them have been good. I think they will take care of you.