PWM Fan not working

[Martell3D]

Hello, I have problems with controlling the fan speed.
Have connected a fan on PWM socket on the card GT2560.
It runs constantly, can not change the speed. Nothing happens when I run M107 or M106. Has been tested with several fans, no can control. Is there a setting in Marlin so I get started PWM fan properly. Fishy, I have now measured the voltage. When I Repetier sets fan at 100%, I get the 5.85 volts, I pull down the slider to 0%, I get 9.98 volts

[bang]

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viewtopic.php?f=24&t=17886