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Geeetech i3 Prusa Pro B fans don't work
Posted: Mon Feb 05, 2018 3:46 am
by molekuul
Hi,
I just build my Geeetech i3 Prusa Pro B, it came with two 2 wire fans, however they don't work. Both fans have 3 pin connector, with only the red and black wire connected. I connected the fans at Fan1 for the extruder, and Fan3 for the boardcooling fan.
What can I do to get these fans working as they should?
Kind regards,
Joris Weijters
Re: Geeetech i3 Prusa Pro B fans don't work
Posted: Mon Feb 05, 2018 8:00 pm
by William
I think you should replace the "Q5"--- AP2306AGN
Re: Geeetech i3 Prusa Pro B fans don't work
Posted: Mon Feb 05, 2018 8:11 pm
by molekuul
Hi Wiliam,
I thought from the schematic Q5 is only for the PWM Fan
not for the 12volt fans.
Kind regards
Joris
Re: Geeetech i3 Prusa Pro B fans don't work
Posted: Tue Feb 06, 2018 1:57 pm
by molekuul
Hi,
I measured the output of the 7812, ther is no power at the output.
There is 12Volt at the input of the 7812.
This normaly means, it's defective, or there is a short circuit behind this 7812.
What is behind the the 7812? Other than the Fans?
Kind regards,
Joris Weijters
Re: Geeetech i3 Prusa Pro B fans don't work
Posted: Wed Feb 07, 2018 5:59 am
by molekuul
Hi William,
I found the problem. There was an short circuit between the + and the - of fan3!
see picture below
https://i.imgur.com/wcmbzEV.jpg
I insert the jumper, now my fans work
I removed Q4 and the 7812
I still don't know what Q4 is needed for.
Kind regards,
Joris Weijters
Re: Geeetech i3 Prusa Pro B fans don't work
Posted: Wed Feb 07, 2018 1:38 pm
by William
Q4 is for
No matter PSU is 24V or 12V
The output interface of fan voltage is 12V also
