The venerable Empire Troubadour.
One of the best.
What cartridge do you use in it?... Empire?

Maybe change the 3 motor grommets. I did, you can get a set on eBay.

If the motor has a bad vibration it sounds like an unbalanced situation.
My thinking is either A/ got some dirt buildup inside on the rotor which is unbalancing the rotor or B/ pole pieces in the stator have come out of thier
holders somehow.
I would seriously think about pulling that motor apart , or have a good tech do it and see what the issue is.