My plotter has an issue... at a loss to what is happening. hoping someone might have some ideas! It has previously worked perfectly, but has started doing this -using same configurations and homing points.

The drawing is fine everywhere except on a triangular portion of the board like this:

The pen draws over the letters twice normally- and in the triangle section, it is dropping down on its second time around- absolutely fine everywhere else- before and after this happens.

Some images of the writing dropping:

I posted some images on the forum previously -
http://www.polargraph.co.uk/forum/polargraphs-group2/general-forum1/whiteboard-polargraph-thread247/

cheers, will try changing the motor current and let you know.

It draws over each character twice- a fraction out the second time - to get the thickness of the lines. So not exactly the same movements being sent. The x-axis seems to be the one that is most effected- dropping down 5mm on its second pass of the character. but outside of the "triangle section" it goes back to normal, even if working on the same character.