megatronics v2 only from usb and no fan control

Hello All

i have bought a megatronics v2 from ebay, i think its a sainsmart as most of them are (correct me if im wrong).

i had a problem with the endstops shutting the board down, i found a cure for that the connectors were labeled different then the original one.


but i still have the problem that i cannot use the board without the usb cable, if i remove the jumper that supposed to make it rely on 12V the board doesnt start. i found some topics related but not stating the same problem i have and how to fix it.
Next to that the fan controller doesnt work, not from repetier and also not if i send a gcode to start it. its not the fan i tested that and it works fine on a 12v line from i atx supply.

i would really like some help cause i cannot find a post from someone with the same problems

regards
Weedz