fan connector?

Hi there,

Just about to finish my new fisher, and it struck me that there seem to be the wrong fan connector on the duet or hotend cable assemby. The cable has a three pin socket with only two populated (oxo) but the connector on the board has two pins side by side (oo).
I've fixed it for now by moving the yellow wire to he middle slot, but I still have to check if the polarity is right. If I have been mistaken about something, please let me know!

I don't have a Fisher, but the hot end fan shouldn't be connected to the FAN0 connector, that's for a controllable print cooling fan. It should be connected to permanent 12V instead, and for that the 3-pin connector is correct. See [reprappro.com].

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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].

Yes I noticed that picture too. At least the building instructions could be more clear. The usage of such a socket would imply a counterpart to stick it on. Is there any reason why the fan should not be controllable? If the hotend is not hot, the fan does not need to be on, so I'd think it is the firmwares responsability to make sure that the fan is on when it has to. As this machine is intended only for PLA, that should be no problem?

The primary use of the fan is the hotend cooling, this is why it is directly wired to the power supply. This kind of setup is considered safer in case of software glitches and preferred by a lot of designers as the effector could be melted if something goes wrong. Here the effector is in acrylic and wood, and may be more immune to problems.

The power supply (19V) is present on the general connector, that why the fan is plugged in .
You probably have already screwed the board on your printer, but on the other face, there is a marking of the functions of all the pins.

As there is no positive positioning of the plug, you shall be very careful to check the pin count as per photos, 2 pins on the left and if I well remember, 15 pins on the right. Trust photos, not me !

Regards, Pierre

The fan must be powered at all times. Like the all metal E3D nozzles, the heatsinks on these nozzles need to be constantly cooled in order to prevent the filament swelling in the cool side of the extruder. I agree that this part of the instruction guide is currently lacking clarity, the image in particular doesn't clearly show that the the socket need to be plugged in 3 pins from the end. I ended up having to refer the schematic to confirm the correct position.

filament swelling? It is intended as a PLA printer right? I've never heard of PLA swelling while hot. I do agree you need to keep the heatsink part of the hotend cool though, as that is where the magic sealing takes place. Molten PLA should never come above the aluminium rim. The insert of the bowden is troubling me a bit though, it shortens the runout space for molten plastic a lot. If the connection to the stainless is not tight/has a gap, that is where a jam will form. I'll try and see on this one.