Heated bed not working

Hi all,




i am fairly new to 3d printing and just recently put together my BQ Prusa i3 Hephestos. up till now i have only used pla so i decided to try some abs.




So i decide to add the heated bed (Mk2a). i soldered the two larger wires to the large pads on the pcb, and the opposite ends i put into D8 +/-. then i soldered the thermistor to the smaller wires supplied with the bed, made sure the legs are spread and insulted before i tapped to the underside of the pcb. then connected the thermisor to the ramps directly above the one for the extruder. i have spent quite a few hours googling as i just can't seem to get the bed to heat up. the lcd displays "bed heating" but nothing happens. i have seen that the temp is displayed on the lcd for the heated bed, but not on mine.




this is the bed i brought http://www.printme3d.com/bq-prusa-heatbed.html




i also got the pursa kit from the same place.




can anyone please help:rolleyes: