Take the Kenwood to a table. Assuming that it is a belt drive, remove the platter, and the spindle too, if you can. Clean the well and the spindle with a Q-Tip and some alcohol, and put a few drops of fresh oil in. 3-in-1 electric motor oil is OK, easily available. Also slide a drop or 2 into the bearing of the motor, where the shaft enters, under the pulley.
You may need a new belt. Clean the belt, and the belt path, with alcohol.
If there are any speed adjustments on it, a bit of contact cleaner to their innards will Help, too.
I'd take the other one back, if possible.
Keep them spinning.