Unusual WT Versalex Noises

I now have two WT Versalex turntables in two different systems. The brand new one is making two noises that are unusual in my experience. One is a scratching noise that my dealer feels is the string and therefore normal because of the nature of the material involved. I tend to agree with the string as the source of the sound, but how can the exact same sound occur with two different newly installed string "belts"? The other sound is a soft thump that occurs at a frequency that appears to be about once per platter revolution. The scratchy sound occurs as soon as the platter begins to rotate. The thump only occurs when the stylus is making contact with vinyl. The thump is loud enough to be audible on soft music passages.

Have any of you WT Versalex/equivalent owners encountered these noises? Does anyone have any ideas as to what could be causing these noises? My original WT Versalex is dead quiet in these regards - no scratchy noises and no thumps. Just the way I like it and what I was obviously expecting for the new WT Versalex.

Thanks in advance for any ideas or comments!

Best Regards,
Realise this is an old post. That thump is the knot passing through the Pulley. It nearly drove me crazy. The cure is to get a super fine fishing line and coating with Wax. Hope this helps anyone with the issue.