GT2560 : no control over PWM-Fan
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- Posts: 4
- Joined: Tue Jul 05, 2016 12:15 am
GT2560 : no control over PWM-Fan
Hello,since 2 days I lost controll over the PWM fan.The fan start spinning at full throttle afer power on the printer (Prusa I3b).Tried to send M107 - no reaktion - the manual controll slider in repetier host isn´´t working too.Reset-button on the printer LCD-Panel (reboot) doesn´t solve the problem.
Re: GT2560 : no control over PWM-Fan
Hi,overkill69 wrote:Hello,since 2 days I lost controll over the PWM fan.The fan start spinning at full throttle afer power on the printer (Prusa I3b).Tried to send M107 - no reaktion - the manual controll slider in repetier host isn´´t working too.Reset-button on the printer LCD-Panel (reboot) doesn´t solve the problem.
You can refer to this article to see if the mosfet was broken:
http://www.geeetech.com/forum/viewtopic ... 24&t=17886
-Keep your mind and try to test it.
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-Everything will be fun!-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
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- Posts: 4
- Joined: Tue Jul 05, 2016 12:15 am
Re: GT2560 : no control over PWM-Fan
Hi, Thank you for your fast reply - there is no optical damage on the MosFet - but I checked with a DMM - there is a short between source,Drain and Gate.I need a working Board.
Re: GT2560 : no control over PWM-Fan
Sorry,i don't understand what you exactly mean.overkill69 wrote:Hi, Thank you for your fast reply - there is no optical damage on the MosFet - but I checked with a DMM - there is a short between source,Drain and Gate.I need a working Board.
-Keep your mind and try to test it.
-Everything will be fun!-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!

-Everything will be fun!-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
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- Posts: 4
- Joined: Tue Jul 05, 2016 12:15 am
Re: GT2560 : no control over PWM-Fan
The positive (+) cable from the Fan is connected to +12Volt - the Negative ist connected to the PWM output signal from the mosfet transistor - the mosfet ist controlled by the PWM-Pin from the Atmel (gate).If the mosfet has a short between drain and source - the negative connector of the fan is permanetly on ground.The Atmel cpu has no control to switch the fan off,or reduce the RPM via changing the PWM signal.
Re: GT2560 : no control over PWM-Fan
You are right.But this short circuit problem must be caused by the mosfet itself,in other words,maybe the components in the mosfet has broken,so it brings the short circuit between drain and source.And we just need to exchange another mosfet it can be work,am i right ?overkill69 wrote:The positive (+) cable from the Fan is connected to +12Volt - the Negative ist connected to the PWM output signal from the mosfet transistor - the mosfet ist controlled by the PWM-Pin from the Atmel (gate).If the mosfet has a short between drain and source - the negative connector of the fan is permanetly on ground.The Atmel cpu has no control to switch the fan off,or reduce the RPM via changing the PWM signal.
-Keep your mind and try to test it.
-Everything will be fun!-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!

-Everything will be fun!-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
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- Posts: 4
- Joined: Tue Jul 05, 2016 12:15 am
Re: GT2560 : no control over PWM-Fan
Yes,that is right, the printer is in warranty, so i need a working Bord for exchange. I'm in contact with Lemon Wang from geeetech, maybe he can send me a mail how i get a working board.