Rattling A20T

[Princy557]

HI
Has anyone had a noisy A20T? I mean rattling and a shakin level. If so how was it fixed, and what causes it?

Observations on mine are the Y-Axis is far too tight. It won't slacken either. It twangs like a guitar.
They, (support), say it couldn't be that and fair do's are sending me a replacement.
I have all the knuts and screws slackened off and then tightened in the slack position. But it still twangs when plucked.
Any ideas anyone.
They, (Support), have also said, to drop the speed to 50% or less, but it didn't help I tried it at 30% same problem.