Mini v2 does not go up after finishing printing


I have a Monoprice Mini v2 3D printer and it has been working okay. A few days ago it started staying at the last place when it finished printing. It puts our a little more plastic and then cools off and the last piece printed sticks to the nozzle. It comes off and the next print starts okay but it leaves a glob of material on the print that has to be filed off. Always before when it finished printing it went up to the top and the finished print was okay. I have modified the print bed so that the wires go out the back instead of being under the bed. Being under the bed caused the wires to frey and the bed temperature would not register. Going out the back of the back of the base and the heat bed did not cause the problem with not going up after finished printing. It worked fine until a few days ago. Do I need a new motherboard?