used a MOSFET like @BigBeau suggested but it blew up a PWM fan by connecting it with the MOSFET via power (worked for a day and then made a loud bang). apparently it's better if you connect the fan directly to power and the PWM wire to the MOSFET... learned that the hard way i guess.
after getting a new (non-PWM) fan it worked fine!
Anyone know how to make PWM work, seems to be running all or nothing
@MoM0_682390
if you use a PWM fan, you need to change the cycle_time in your printer.cfg to something like █████ (see edit)
but as stated in my comment, it blew up my PWM fan! you could try connecting the fan directly to the power supply and only just the PWM wire to the controlboard.
Edit:
check your fan's datasheet.
if there is a preferred control frequency, use that.
if there isn't, 25kHz seems to be a common value. (which would be 0.00004 in Klipper) (edited)
I recommend folks use mosfet relays labeled for bed heaters on amazon - the ones in the wiring image (as well as may others online listed as mosfet switches) use the f5305s P-channel mosfet, which isn't really meant to handle more than 20v maximum. I had ordered the ones in the image and both burned out on me within an hour of use, both failing high. This is obviously a huge safety issue, especially if it were hooked up to a chamber heater. I used a mosfet meant for bed heaters and its been working great.
@BigBeau I also had a hard time finding mosfets rated for a 24v signal input. Did you need to change any of the wiring to use the heated bed mosfet instead? Also most of the heated bed mosfets look rather bulky, did it cause any trouble fitting it in nicely?
@WillStrain_1967462 the only modification I made was removing the mosfet heatsink. it's not even switching an amp so its pretty much unnecessary. I did have to trim some of the plastic off the underside of my k1c to vhb tape it but I could have just made a mount or chosen a smaller board instead (like the DiGiYes one on amazon)
Wiring didn't have to be changed, it's the same as in the included guide
Fantastic design. Not sure ill use it as of now, since the set up I have works well. In saying that, more people should print with the enclosure closed, better print stability, healthier and more quiet. This is a %100 quality of life improvement if peeps don't have their own solutions.
Thank you for this design!
Any update on the wiring schematics?
@LukaBozhich_2257566 I guess I forgot to hit publish and saved a draft... It is now up and I have included a PDF as well.
Looking forward to seeing the wiring schematic and configuration instructions. This looks like the exact upgrade I need. I can't believe how wimpy the stock exhaust fan is. Thank you for creating this
Hi! I am very interested in this project; however, can you share more details on why we should not connect the 120mm fan on the existing port? Is it mostly due to the power ratings or something else?
@Chedomir_D_1207095 The original fan header can only support 2.4W of power to the connected fan. A 120mm blower fan at minimum consumes 12W. That is 5x the limit and will destroy the power delivery circuitry based on what I can see from reverse engineering the motherboard and inspecting components.
You need to power the blower fan without using power directly from the motherboard. I am still working on the wiring guide and diagrams (I did the original wiring months ago and lost the schematic). I should have the guide up by this weekend once I triple check and validate everything.
@PurpleR0b0t_2061213
I love the idea of your system, mostly because of the ability to use a carbon filter with more pressure and the higher airflow through the small hole of the original fan. As a bonus, the noise should be lower too. Please upload the schematics for the wiring. I'm eagerly awaiting them.
