My prusa has a PCB Heatbed MK1 and for some reason it won't heat up to 110C. The hotest it will get is 100c after an hour and a half. I'm using pronterface to control the printer and ABS filament. The extruder heats up without a problem and i find that I can start printing when the heatbed hits 100C but it's generally hit or miss. What could be causing this issue?
