dishlex global 300?

i have just replaced mother board as it would pre wash then go on to wash cyc le and trip out safety switch .since putting in new motherboard it now trips out safety switch on pre wash within a couple of seconds. my 2 year old daughter used to open the door while it was turnt on and the last time she did that it tripped out safety switch. how can i fix i have 6kids and im sick of washing dishes by hand.