3DP Part Cooling Fan 5015 Replacement for Gen 1 extruder

Hi! I was just wondering if anyone had used the same type of fan…

The fan is typically used on remote control esc’s and is 5v.

I have replaced the original 24v fan with this and used a step-down converter to match the voltages. It is a huge improvement over the original although it is noisy

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I just tried to connect the extra cooling fan. But during the test, when I was using multimeter to check the voltage, I seemed mistakenly made a short circuit and saw a spark.

Now even I have reverted the circuit to the factory status (removing the Y splitter and re-connect the factory part cooling fan to the board), the part cooling fan always runs at likely full speed after the machine is powered on.

I also tried to send M106 and M107 command through Luban, but the fan just does not stop.

Is there any possible way to fix this? Thank you guys.

Depends on your soldering skills. Most likely you killed the FET controlling the fan. It’s not too difficult to replace if you’ve soldering skills. Before you do that, perhaps check if the GPIO pin that controls the FET changes state on M106/M107. If not, perhaps this is damaged, and not the FET. If so, things might be more difficult…
If it’s the FET, cost are noot too high - a FET costs typically less than 1 buck.

Hi @Hauke ,

Thank you for your suggestion! I am not so familiar with electronics. How should I check the GPIO pins? Check the voltage through multimeter?


It’s mostly magic for me too. I would try contacting snapmaker, maybe they can sell you spare board - Support Ticket Form

Here’s a bit of background: Variable Speed Cooling Fan for Raspberry Pi using PWM (video#138) – SensorsIOT

So basically you have some controller (in the link above a Raspberry Pi, in the 3DP toolhead it is I think a STM MCU) which gives logic level “high” (i.e. 5V or so) for “Fan on” and level “low” (0V) for fan off. “Fan on 50%” is done by very quickly switching from low to high and back again (PWM, pulse width modulation). However, the GPIO pins of MCUs or Raspberrys cannot directly drive a fan, they are not capable of handling the necessery currents. So you need a driver, typically a transistor, and nowadays usually a FET. This is either connected directly to the MCU, or has the two resistors as shown in the link - depending if the MCU already contains such resistors.

Answering your question: Yes, use a multimeter. Issue the command “Fan 100% on” and see if the GPIO pin goes to logic high, and issue “Fan off” and see if it goes to low. If you see the difference: MCU/GPIO is OK, FET most liekly broken. If you do not see the difference: Unsolder the FET - and then check again, because it may be that the FET “shortens” the GPIO and will pull it to low or high regardless what the MCU says. Check again with desoldered FET. If voltage on GPIO still does not change - MCU most likely broken.

Thank you for your detailed explanation!

Do you know where I can get the spec of the controller of the 3d printer toolhead so that I can find out which one the GPIO pin is and which FET controls the fan1?


I’m not aware that the circuit plans of the Snapmaker parts are available anywhere. However, whatever I’ve yet seen, they do use single or double layer PCBs, i.e. you can relatively easily trace the copper and thus work your way through the circuit. I guess I’d start with the connector of the fan, look to which FET it connects, find out which is the gate pin (drain will be connected to fan, source will be connected to ground, what remains is gate), then look where the gate pin takes you on the PCB - either a resistor, the MCU or to the plug. If it goes to the plug, then PWM signal comes from the main controller. If it goes to the MCU, you have your GPIO pin. If it goes to a resistor, check if resistor goes to ground. If so, you need to find the second resistor or will get to the MCU eventually. If it is a second resistor or the first resistor does not go to ground, that resistor should then guide you to the MCU GPIO pin.

Btw. - is it a first generation 3DP head (i.e. no slits on the front), or a 2nd gen (air intake slits at the front)?

Thanks for further explanation!

Mine is the 1st gen (kickstarter version), no slits.

Hauke via Snapmaker where creation happens <notifications@snapmaker.discoursemail.com>於 2023年9月16日 週六,上午4:55寫道:

OK - I’ve the same. if you get stuck, I may have a lookinto ine - but only in about one week, currently not near my machine.

Thank you for your help.

If I understand it correctly, this FET should be the one controlling the part cooling fan(fan 1).

I will then try to find out which GPIO pin connects to it.

Is there any conclusion for this topic? I also have one Rev1 head and wanted to print this Mod. But i saw multiple designs, read something for defect FETs and diodes.
Is there an instruction what parts I need and how to assemble? These are so many posts and so much content run next to another. Really hard to read.

That looks about right. Not sure if Fan1 or Fan2 was the cooling fan, but I think it was Fan1, so that matches up. The two resistors nearby are most likely the ones I/the linked post mentioned. So you need to take this into account. Most likely the 1 Ohm-Resistor (“010”) goes to the GPIO.

Do not get discouraged - I agree, the thread has gone a bit unwieldy…
Basically you “only” need the additional fan. For safety (and most likely not really needed) you can add a 1N4148 diode as flyback diode.
If you do not by accident shorten anything (like sedc unfortunately did, which may kill components), the procedure is simple and uncomplicated, and the increase in print quality in certain situations is considerable!

Thanks for your hint.

I find it’s a little hard to read the circuit since the PCB board is black and the circuit is not printed in an obvious color. I even cannot identify the width of the segment of the circuit(it’s a thick line or two thin line).

I will keep trying.

You may also use your multimeter to check assumptions made based on the copper tracing. Just measure resistance (or use continuity tester function) at the supposed ends of the copper line - 0 Ohm means its connected :slight_smile:

I found the MOSFET controlling Fan1 is broken in appearance. Then I tried to unsolder it but my soldering skill is not good enough to get it done. Besides, I also found the MOSFET, which is NCE0102 according to the number printed on it, seems not easy to find in Taiwan.

So, I ordered a new board from Snapmaker. The current board will be used for soldering practice. I will still try to find other tools to unsolder the FET and to see if I can find any replacement in Taiwan

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Seems to be quite a standard N-Channel MOSFET. If you can’t find the exact model, look for others that you can get which have roughly the same data - this is nothing that needs precision.

It seems most of the electronic shops I know in the city I live don’t sell many kinds of MOSFET, especially those in SOT-23 package.

Here is the spec of NCE0102: https://datasheet.lcsc.com/lcsc/1809291523_Wuxi-NCE-Power-Semiconductor-NCE0102_C161843.pdf

And I found these on the websites of some electronics companies in Taiwan:

They have similar specs with NCE0102 but can only be sold through the websites.

I don’t know much about transistors. Please let me know if I misunderstand the specs and these models cannot substitute NCE0102.


Yep, both you found would work - admittedly, I’m also only a hobbyist and some finer details may be lost on me, but to my understanding the important characteristics are V_DS (max Voltage the MOSFET can control - we need 24V), I_D (this would be the max current the fan(s) can draw through the MOSFET, and 2A is definitely enough), Power Dissipation (max value of “heat” they can get away with). Also frequency behaviour might be relevant, but with the low PWM frequencies the fan uses, there’s a lot of headroom.