I got a RepRapDiscount Full Graphic Smart Controller from ebay. I have it all working but the SD Card part kinda... If I power the Prusa i3 up then put the SD Card in the slot. Marlin 1.0.2 does not see the card. If I leave the card in the slot, power down 10 sec, then power back up. Marlin 1.0.2 then does see the files on the SD Card and can print from it. Why can I not just pull the SD Card in and out like I see other youtude videos doing?

There are two metal tongues on the sd-card housing. The one on the side is telling, whether the card is locked (writeprotected) or not.

The other tongue tells if there is a card or not. Maybe this tongue doesn´t make good contact?
-Olaf