Cooling fan always stays on

[shanemerrick]

I have a cooling fan connected to my i3 al pro printer, and all was working well for a while, however I used the LCD menu control to 'stop the printing' and it caused some issue with the control board. Now I have no control over the cooling fan as it is always on. Has anyone encountered this before? I suspect it's a bug with the code.

[bang]

You'd better check which socket you connect your "cooling fan" to,it should be connected to the "PWM_fan" socket if you wanna control its speed.
As for the "stop printing" function,it will take some time for the motherboard to make the response so just wait a moment to take a look.

[shanemerrick]

Yes, it's the PWM socket that is no longer working. I've check the voltage and it is always 4.3v no matter what speed setting I have the fan on.

[bang]

Then maybe the mosfet that controls the PWM signal was broken,you can refer to the two posts to verify it:
viewtopic.php?f=24&t=17886
viewtopic.php?f=13&t=17443