Savalo before i can tell you if there is any chance that this spirit can take over your body i need to know few things(do not worrry no spirit can take over you for long time ) .
Have you been possesed by any way before ?And if you were i need to know was it physical and you lost your memory while that occured ?Or was it more like you shared your conscious with something else for some time ?
Also when you use the pendulum and the board do you hear a the answers in your mind ,while the pendumul is writing the words or you do not know and you just observed the letters which pendulum showed ?
Think carefully before you answer me ,because that will narrow the possible outcome of what this spiri (alive or dead ) told you .
I agree you need to sage out the board ,but do not forget that the board is just tool what really does the connection and allows the spirit to use the tool is you (either consciously or subcosnciouslly ).
Keep in mind not all spirits tell the truth !
Learn to cast circle or to perform lbrp before using the pendulum and the board ,allowing only good entities to pass through .You need to sage out yourself too and the house also .Block the connection with this spirit as soon as you sense it by casting the circle or using visualization imagine shields of energy .
Also keep in mind some people consider burning the board to do more harm than any help .