I've have been successfully getting constant results guiding my iOptron iEQ45 with PhD for a while now until I had to replace the Dec circuit board in the mount a few weeks ago. Now the Dec guiding has a funny pattern where the dec moves off 4 to 6 arc seconds in one direction then goes off in the other. See the graph below. I'm using the default settings in PhD as I have always. Does anyone know why this is happening?
Any help would be greatly appreciated.