Tool Fan / Fan 0 quit working.
-
So I am very confused on what happened.
Setup:
Duet 2 Wifi via 24V
Fan 0 = Part Cooling fan
Fan 1 = Hotend Fan; enabled when hotend is above 45C
Fan 2 = Enclosure Fan; when MCU is above 45C, when Stepper warning at 60Cconfig.g fan profile:
; Fans
M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on
M950 F2 C"fan2" Q500 ; create fan 2 on pin fan2 and set its frequency
M106 P2 X1.0 S2 H100:101:102 T45:65 ; set fan 2 value. Thermostatic control is turned onTo be clear this all worked fine a few days ago and earlier this evening.
The ONLY change I did tonight was to the enclosure fan. It is 12V and I was running it at low 24V until I finally wired in my buck converter tonight. Thats when the fan 0 quit working. In Web Control it shows at 100% but nothing happens. The enclosure fan (fan 2) and hotend fan (fan 1) still operate normally with temperature.
Things I've tried:
- If I unplug the enclosure fan it still does not power up fan 0.
- If I plug in the fan 0 pins into the always on pins, the fans power up just fine.
- When fan 0 is at 100% in Web Control, a small hum can be heard.
Can only a single fan control be fried? This seems very odd to me.
-
I suspect the fan0 mosfet may have gotten damaged during the buck converter operation.
Can you see any damage to the tiny little chip near the fan0 port?
See the photo here: https://duet3d.dozuki.com/Wiki/Connector_and_spare_part_numbers#Section_Fan_mosfet
-
@phaedrux Thanks for the look at the mosfet. Probably could have started there.
Mosfets appear intact though. Any other components to check? Like I said there is a small hum when the fan is activated, so I believe the mosfet is switching, maybe where ever the power is passing through to the mosfet? Sorry not super familiar with board electronics but can diagnose and identify components I have some guidance on where to look.
-
@fickert said in Tool Fan / Fan 0 quit working.:
until I finally wired in my buck converter tonight.
Let's start with that then. How do you have the buck converter wired up?
Fan0 is a 24v fan?
The fan mosfet doesn't always fail in a spectacular and visible fashion, so you might not be able to tell by looking at it. If you have a multimeter with fine tip probes and a steady hand you can test the mosfet itself to see if it's functional. If you're not already familiar with that kind of thing it might be best to check some youtube guides for how to perform the test. It's a tiny mosfet though, so it can be quite tricky to get the probes in and steady. And due to the location on the board it's also very easy to slip and short something else out.
The fact that the fan is working ok when using an always on port, and that your config is essentially correct and unchanged from when it was working indicates that the mosfet is the problem.
-
@phaedrux buck converter is wired to fan 2. Simply has the fan 2 output pins wired to the voltage input of the buck converter, and I calibrated the buck converter to step down 24V to 12V on my bench supply before installing it. The fan on fan 2 works as intended.
I am likely going to chalk it up to a bad mosfet. Luckily I should have a spare or two from an older duet board I fried a while ago.
-
The negative lead of the fan needs to be directly connected to the negative terminal of the fan header because PWM is switched on the negative side.
