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When should the Hot End Fan be running? UM2+

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Posted · When should the Hot End Fan be running? UM2+

Hi,

tried to find some information about the hot end fan - but could not find if it should run

- always

- only together with the two fans on the print head side

- sometimes - depending on - ???

The settings in Cura obviously only apply to the two print fans, so how about the "hot end fan"?

Regards

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Posted (edited) · When should the Hot End Fan be running? UM2+

On an UM2+ I think the "hot end fan" come on at 40 degrees, on older models they are on all the time

Edited by Guest

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Posted · When should the Hot End Fan be running? UM2+

Ah, ok, thank you.

So I suppose if it is not moving at any time, something is wrong - either fan or power from board. Well, so I will disassemble the printer and see what the root cause is.....

By the way, I got aware of it when I tried now since several months to get rid of the failure of prints.

When printing the base level (first slice) on larger prints (estimated > 5x5 cm) it already begins to be faded. First part ok, then, when it fills the first level the extrusion begins suddenly to slow down, then no extrusion. It looks like the heat is "crawling up", softening the filament in the part above the white insulator and in the first part of the bowden tube. Then the filament is creeping/being pressed into the small gap between bowden and insulator and no longer pushed through the nozzle. Then it obviously hardens and "grinding begins".

I have played with several combinations of temparature, speed and material flow, nothing helped. But when the fan is not cooling the upper part, its is obvious why it happened.

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Posted (edited) · When should the Hot End Fan be running? UM2+

My suggestion is to check the fan connector which is inside the print head block, IMO its a design flaw - the wires are only crimped on to the connector.

On my printer this has become detached several times, the same applies to the two side fans.

In my case I have soldered the connectors which has improved reliability for me

good luck

Edited by Guest

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Posted · When should the Hot End Fan be running? UM2+

Hi,

well, the fan is ok. I removed the cables from the connector at the main board and tried with external power - the fan moves. I suspect, that I made a mistake when reattaching the hot end cable during the upgrade from UM2 to UM2+.

The problem is: where to attach the cable correctly on the board? The mainboards I can see in the upgrade manual as well as in the general assembly manual V1.1 are different from mine. There is no connector in the middle of my board - the one below the "ti" from the printed word "Ultimaker" on the board. There is only the one above the "e". And the naming of the other connectors do not show any "Hot End Fan" ...... well, will check with support about the schematics....

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Posted · When should the Hot End Fan be running? UM2+

Don't forget to check the print head cable, i.e. the cable going from the print head to the board.

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Posted · When should the Hot End Fan be running? UM2+

There is no connector in the middle of my board - the one below the "ti" from the printed word "Ultimaker" on the board. There is only the one above the "e".

Don't use the connector above the "e". That's a jumper that changes the stepper driver for the z-axis from 8 to 16 micro-steps.

AFAIK the hot end fan was connected to the serial connector J22 on the very early mainboards. Pin 1 is 5V, Pin 2 is GND

Here is a picture from 2014: https://ultimaker.com/en/community/5038-um2-electrical-wiring-questions#reply-33286

Here is a pdf with the schematics: https://github.com/Ultimaker/Ultimaker2/tree/master/1091_Main_board_v2.1.1_(x1)

j22_serial.thumb.png.ca2cbd016e6e1ee854325509bcc79296.png

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