Printing from the SD Card.

I use USB from my laptop computer. I can extrude but not retract. I did use Repetier-Host. The extruder was not cold. AND I can not getfrinting from the SD card to function, only USB.

Hello I have a problem with my RF1000. It does print OK.
But I can not reverse the feeding of filament to extruder.
It does not go backwards when I try to press the button for reverse direction of filament.
What can I do?
Uffy