Duet Dead

My duet has some how fried. When I plug the USB cable in it gets extremely hot, and there is soot on a row of capacitors/resistors. The heat control for the hot end disappeared, the fan turned on and the grey plastic around the hot end melted.

Is there anyway to get a duet repaired without buying a new one? Attached is the location of what seems to be the damage.

Cheers,

Richard

Edited 1 time(s). Last edit at 07/04/2014 04:55PM by BeebBenjamin.

Those SMD components can probably be replaced if you are decently skilled at soldering, but it's not certain that those are the only thing broken, and it may be some other short circuit that caused those to get fried. Depending on what happened to it, it might be possible to get it replaced under warranty.

The only component on the board which seems to be fried (upon visual inspection) is inductor L7 on the GNDANA line. Sorry if I sound dense, but what does this module do? It looks like it steps down to ground for some kind of surge protection. Why would this screw up the current going through the system?

If L7 is fried then unfortunately this probably means that 12V was somehow connected to the ground side of the bed thermistor or the hot end thermistor. So I suggest you check your thermistor wiring very carefully before proceeding. In particular, check that the ribbon cable connector is central on the pins on the Duet board, not displaced up or down by a pair of pins. The Duet board ought to have a proper shrouded and polarised connector in that position, to prevent the connector being plugged in incorrectly.

If the ribbon cable wiring is OK, check the wiring of the 6-pin hot end connector.

Once you are certain that the wiring is correct, you could replace L7 with a wire link without significantly affecting the operation of the circuitry - but if L7 has fried then the SAM3X processor has almost certainly fried too.

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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 soldering a bridge across the inductor might fix it? I think the controller is screwed too, because I can't talk to it anymore. If I bought a new processor and inductor, could I use my workshop at work to fix it?

Quote
BeebBenjamin
So soldering a bridge across the inductor might fix it? I think the controller is screwed too, because I can't talk to it anymore. If I bought a new processor and inductor, could I use my workshop at work to fix it?

Unfortunately, if 12V has been fed into one of the Duet pins, it is possible that it has fed out through other pins and damaged other ICs on the board, such as the 3.3V regulator and the stepper drivers. However, the processor is only GBP8 from Farnell, so if you have a hot air rework station, you could try replacing it. Without a hot air rework station, I wouldn't bother.

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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].

Ah crap, expensive paperweight it is then. On closer inspection, one of my cables came loose, it must have been the culprit (it was one of the hotbed power wires). Mine came with screw terminals (from think3dprint3d) so I guess there is always the risk of this happening. Does no one offer a repair service for these boards?

Repair of a board that has been fried in the way you describe is likely to cost more than the price of a new board (it's cheaper to populate & reflow a complete board robotically than replace several components by hand) - and in many cases is virtually impossible because the heavy current has burned out PCB tracks or heat has oxidised pads as well as destroying components.

Dave
(#106)

Edited 1 time(s). Last edit at 07/07/2014 06:03AM by dmould.

Same issue here. I fried my L7 inductor trying to hook up a mosfet driver for an extruder fan. I am not sure if the mosfet driver was the issue or my multitester probe shorting things. I really need to stop blowing this inductor. Given the frequency of my stupidity, I attempted to use my rework station to replace the inductor or short the burnt connection. When I removed the inductor this is what I saw (see attached image showing no clear pad to attach a new component). Oh well. At least my multiple board purchases are supporting the project (?).