PWM Fans work with some fans but not others
-
Hi there,
I have a weird issue. I recently upgraded my hotend and blower fans and I am finding that they don't work on PWM Fan0 and Fan1 slots. Previously they did work and when I swap back to the older fans it work again. This rules out a blown board. When I put the new fans in the always on fan slots they both turn on and work.
Am I missing something? I have tired turning them on via Web GUI and Gcode with no luck.
-Arland
-
Fans vary in their response to PWM. Some work great, some need to be blipped, some don't work at all. No way to predict.
-
How do I modify this? I can hear both motors whining so they definitely have power.
-
Some fans just don't work well with PWM. You have to use fans that work.
-
Gotcha - I am using the Slice Engineering hot end fan for the mosquito and the 5015 fan from https://www.th3dstudio.com/product/5015-high-speed-ball-bearing-fan-24v/ from TH3D.
-
Adding to this - the fans that used to be there were always on. It seems like PWM never worked
-
https://duet3d.dozuki.com/Wiki/Gcode#Section_M106_Fan_On
You can try playing with the PWM frequency value. 10 to 30000 are valid.
Adding B1 for a full second of full power can also help kick start them.
But not all fans play nice.
-
I am at a loss - nothing seems to work on this. The old stuff just runs at 100% and the new stuff doesn't run at all.
-
Okay had a breakthrough. It seems like Fan0 and Fan1 don't work but Fan2 does. Is this a setting issue or something wrong with the board? Should I get it RMAed or am I missing something?
-
@Arland, you can connect a small 24V or 12V (depending on your VIN) bulb instead of the fan and see if it responses to PWM settings. If it does, the board is probably ok.
Some fan models do not work well with PWM. Actually I am surprised that some fans do work since their electronic gets intermittent power.
-
It sounds like you may have some damaged fan mosfets. The first post made it sound like they were working at first though with different fans?
If you post a close up photo of the fan port area we may be able to see if there is visible damage.
M106 P0 S1 sent at the console should enable power to flow, you can then measure the port pins with a mutlimeter, careful not to short anything out. Depending on how the fan voltage select jumper is placed, you should either see VIN or 5v.
-
@Arland said in PWM Fans work with some fans but not others:
Okay had a breakthrough. It seems like Fan0 and Fan1 don't work but Fan2 does.
Is it by chance a Duet 2 Maestro board? They have independent Vfan jumpers for Fan2 vs Fan 1 and 0.
-
@bearer Good point, we didn't really gather the basic info off the hop.
@Arland https://forum.duet3d.com/topic/5909/guide-for-posting-requests-for-help
-
Thanks for chiming in guys.
It is a Duet2 Wifi.
Regarding the fans - When I plug the old fans in they still spin, but I don't seem to have any PWM control. Both new fans work on Fan2 as well as the old ones. I think it is safe to say it is isolated down to the ports. Are the mosfets independent to the port?
I used a multimeter and the M106 P0/P1 S1 it looks like I am getting 14-16 volts on fan0 and fan1. Which explains why the 24 v fans aren't spinning - just making noise.
-
That looks like a blown mosfet to me.
They are replaceable if you're comfortable with your hot air soldering skills.
https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Fan_mosfet
-
Hm - you are right. How does Fan1 look? They both don't work.
