I have emailed support but thought I’d ask further opinions.
My machine has always had a ‘judder’ when pen is returing to origin. The judder is now effecting my plots whereupon it’s slipping and juddering mid-plot especially when pen is nearest x-axis. It’s been looked after well, the odd spot of machine oil once in a while and has a dust cover. Do you think the belt is loose?
If the belt is loose, it can definitely cause that.
The easiest way to adjust it is to loosen the two set screws on the bottom side of the Tail Block. The 5/64″ (ball-end) wrench included with the AxiDraw is the correct one to use, and you should need to use the short (straight, not ball) end of it to loosen or tighten those screws. This will loosen the Tail block from the 6 mm (Y) shafts; you can vary the tension by shifting the exact position of the Tail Block with respect to those two shafts. When you are done, tighten both screws securely with the short end of the wrench.