RDS Head not settling well after rotating

[[Tr...]]

One of our CMMs has a VAST XXT RDS head. A few weeks ago it started taking longer to finish a rotation to the down position with our longest styli. It flips back and forth until it is able to settle in that position. The number of back and forth swings that the head does to complete the rotation to the down position has been increasing over these last few weeks.

Do you know what would cause this? How can I fix it?

Thanks,
Tracy Gilchrist