Brother doesn't want you to service the machine yourself, they say this in all of their manuals, have for years. My BFF has a PE770 that had an awful squeak and when we took to the dealer they were great about finding it and showing her where to oil it. I'm thinking not all dealers are like this. As much as I love my vintage Brothers, one of the reasons I don't want a new (or a newer) one is just for this reason. I prefer machines I can service myself. Your machine even though it was bought used should be under some kind of warranty that includes a cleaning/oil service.
Cari