I don't think the OP was suggesting the mis-track is only occurring on test discs.(?)
The fact that the arm skips towards the centre suggests that incorrect platter level could actually be part of the problem(???)
Worth re-checking it and fine tuning for a perfectly level surface then re-assess with normal discs.
The fact that the arm skips towards the centre suggests that incorrect platter level could actually be part of the problem(???)
Worth re-checking it and fine tuning for a perfectly level surface then re-assess with normal discs.