Fan1 Stuck on!

handyandy

Hi, I am working through a new build printer and have another problem.
Using my Duet 2 WIFI board I have Fan0 connected as the print cooling fan and Fan1 as the extruder fan as you would expect with the following lines in my config.g file.

M308 S1 P"e0temp" Y"thermistor" T100000 B4725 C7.06e-8
; Configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1 ; Create nozzle heater output on e0heat and map it to sensor 1
M307 H1 B0 S1.00 ; Disable bang-bang mode for heater and set PWM limit
M307 H1 R4.153 K0.495:0.000 D3.20 E1.35 S1.00 B0 V24.3 ; Results from act PID tuning
M143 H1 S290 ; Set temperature limit for heater 1°C to 290°C
;
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 at 45°C
;
Tools.....
M563 P0 S"Extruder" D0 H1 F0 ; Define tool 0 (extruder)
G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0°C

The problem is that whenever I turn the printer on fan1 is on full speed and will not turn off.

I Have a spare fan and have tried it in all 3 fan positions. In fan0 and fan3 it works perfectly. The speed can be altered as required or switch off by sending the M106 commands directly to the dashboard. In fan1 the fan will only run at full speed and can not be turned off. This is a simple test but seems to pinpoint a now faulty board.

None of this happened before the rebuild as is always the case!!

I think it was during PID tuning that something happened? I completed the bed fine, but the nozzle seemed to be working as expected until nearly over then the red graph line suddenly became extremely erratic with wild fluctuations in the stated temperatures as well. I also briefly saw a warning for (I think) an open circuit.

Do you think a heater/thermistor fault in the Hemera Revo extruder has fried one of the mosfets on the Duet?

The only solution I can see at the moment is to replace the board (with what?) and the Revo heater/thermistor block?

gloomyandy

@handyandy I think you need to separate out the fan from the temperature sensor. So what happens if you change the two M950 lines so that F0 uses C"fan1" and F1 uses C"fan0", can you now control manually the fan connected to fan1? Is the fan connected to "fan0" running constantly?

droftarts

@handyandy It could be the fan has shorted out, which might explain the erratic temperature readings. Try connecting it directly to the PSU to test it. It also sounds like it may have cause the fan MOSFET on Fan1 to fail. You may be able to see this; for an example of a failed fan MOSFET, see https://docs.duet3d.com/en/User_manual/Troubleshooting/Parts#replacement-parts

If you can get a close up picture of the fan MOSFETs, and post it, it may show what happened. I expect the Revo heater is fine, and probably the thermistor is okay too.

Ian