Hi David @dc42 ,
Thanks for your help and suggestions! My knowledge in electrical engineering is very limited so pardon my silly questions. I use duet v1.01, may I know where is the MOSFET source pin? I am trying to write the procedure in steps based on my understanding.
Check the resistance between V_FAN pin of FAN_0 and V_FAN pin of Always on Fan
Check the resistance between MOSFET source pin and ground pin of Always on Fan - Where is the MOSFET source pin in Duet wiring diagram
For Step 1 and 2 what are the typical resistance values?
Connect the pump with thermistor to one of the PWM control fan pins then measure the voltage between:
(i) Negative pin of the PWM fan connector and VIN Ground terminal (-ve pin of the power input)
(ii) Positive pin of the PWM fan connector and VIN Ground terminal (-ve pin of the power input)
(iii) Mosfet source pin and VIN Ground terminal (-ve pin of the power input)
In the duet wiring diagram, if you can indicate where is the MOSFET source pin, it will be helpful.
If it involves a high probability of blowing up a MOSFET, I rather prefer not to do it because I do not have the skills to solder them back.
Thanks again for your help!