I have not followed all of this thread,,, because I no longer own a DeWalt but I will ask/suggest two things... Check youtube if you have not.... That is my first go to repair place.... There are videos on all types of repairs/rebuilds on all types of equipment.... and two, I know there are two, maybe more sites/videos on the DeWalt scroll saw...and I think they are mentioned in this thread.... . If they do not discuss your problem.... have tried to email them and let them listen to your recording.... They may be willing to help.... Having owned a DeWalt scroll saw,,, I know you have a problem.... It does not sound normal,,, at all... but it may and probably is an easy fix...