Control board Fan not turning ON

[Stunzasr20]

Hi
Just wondering when the control board fan turns on? I have not seen it turn on yet. Is there a set temperature in the firmware that it turns on? I haven't looked through the entire firmware but thinking such information might be in there, or should it come on the moment the printer is switched on. The extruder fans turns on the moment i switch the printer on.
Printer is Aluminium Prusa I3, with sanguinololou board and a brand new setup.
thanks

[Mark]

the fan for the board should be on like the extruder fan, you can interchange the two fans to see if the fan is dead or not, or plug it into the other connector see if it works.

[Stunzasr20]

I plugged the fan into the working extruder connection and the fann for the board came on. So I now need to determine 12v supply and ground

[mhef]

I'm having a similar issue, except none of my fans work, I've even connected 2 new fans to all the fan ports and I'm having no luck. my board is the gt2560 from the pro c.

[Mark]

are all your motors work or not? the fan power is directly from the 12V conversion chip, if the motors have 12V then the fan should be on too. Or how about plug a jumper cap here, see the picture below, then the fan will connect directly to the 12V main power:

QQ截图20160316154041.jpg (217.86 KiB) Viewed 11468 times

[vschiaveto]

I have one mecreatror 2 and started work weird! I noticed that the control board fan has stoped .. so I change to a new fan, but the fan was running too fast, then I checked the voltage and was 24V(suppose to be 12V) and my main power is 24V. I am having strange behaviors with my steppers, some time it move Back and forward very fast making a weird noise.

I think there is something with my control board. but look like they only rev the GT2560 rev A for sale and the macreator2 is GT2560 Rev B.

What is your opinion? should I tried change the 12v conversion chip ? Is possible that conversion chip is causing the stepper problem?