Hot-end fan is not working

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robots inc.
Posts: 4
Joined: Thu Apr 17, 2014 1:57 pm

Hot-end fan is not working

Post by robots inc. »

this is a little long, so bear with me

I am relatively new to 3d printing, the felix 3.0 being my first. One day I decided to experiment with overnight prints. when I woke up in the morning, I found my print only half done, with a small amount of wispy threads clung to the top of it. at first, I only thought that the filament had broken, and that I could keep on printing. But upon closer inspection, it turns out that the one of the leads on the hot-end fan had broken off. An hour and one awful solder job later, i had given up on fixing the fan, so I started experimenting. I took the blower fan out, and put in place of the hot end fan. Sadly, as i was switching the wires on the control board, I must have bushed one against an SMD component, as a puff of "magic smoke" appeared from an indiscernible place on the board.Despite that, the printer turns on and off normally, and every function works besides that one fan. I have ordered new fans, and tried them, but they will not turn on. Do I need to order a whole new control board, or is there a cheaper fix than that.

any help is appreciated
thank you

Legion 2.3
Posts: 84
Joined: Sun Apr 20, 2014 6:23 pm

Post by Legion 2.3 »

Hi robots inc.

You´re lucky that your board is still intact after the "magic smoke" appeared. You don´t need to get a new board, the hot end fans can be connected directly to the 12V main power wires from the power supply. The fans from the Felix 3.0 are rated for this voltage.
That´s even better than before because the fan driver only delivers 5 V, so your fan will have much more power with 12v. This reduces the risc of a jamming extruder.

If your blower fan driver is also defective, you can simply use a mechanic switch to give it 12v, so you can turn these fans on and off if necessary.

It will be a little louder, but it´s worth it.

robots inc.
Posts: 4
Joined: Thu Apr 17, 2014 1:57 pm

Post by robots inc. »

hi legion 2.3

Thank you so much for your input.
One quick question before I go ahead and mess with some wires :)
Do you loose software control of the fans ( I think yes ), and if so does it effect anything? Also, should I connect the wires to the power supply input terminals on the board, or somewhere else ? Your help was much appreciated as I have posted before on this forum, and have been left out in the cold.

Legion 2.3
Posts: 84
Joined: Sun Apr 20, 2014 6:23 pm

Post by Legion 2.3 »

Hi Robot ;)

You can connect the wires to the power supply input terminals. Just be carefull, you get easily copper debris when you remove the wires from the terminals, better look twice before it puffs again ;) .

Of course, you can´t control the hot end fan anymore, it´s always on. It´s only switched off if you turn the atx power off (which happens automatically about 5 min after the print). It doesn´t affect anything else, I did it myself and didn´t notice anything bad since then. Your fan will be a bit louder than before because the voltage is higher than before (5V -> 12V), but your hotend gets a better cooling which prevents clogging.
robots inc. wrote:Your help was much appreciated as I have posted before on this forum, and have been left out in the cold.
Unfortunately, there are only a few members in this forum who CAN help, and not everyone has the time to read any comment and there is noone omniscient, so it happens that a thread stays unanswered.

I´m always happy when I can solve problems :D

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