How often to lube platter shaft / motor
My old '76 Sansui manual reads "Every 3 months or 200 hundred hours of play - lube the platter shaft & motor with a few drops..."
Is this excessive, not enough.... I think the last time this table was oiled was 2 years ago, and it still works great.
Watch those close Turntable spindle tolerances!
Turntable spindles are (usually) made with a VERY close 'fit' to the supporting bearings.... otherwise rumble and wobble would be excessive. That said, you want to use a very light oil to match these fine fits. Mobil-1 0W-30 is your best and safest bet.
Marvel Mystery oil is NOT compatible with many (most) synthetic oils, and neither is automatic transmission fluid because most synthetics will precipitate the detergent additives in trans fluid. The result is not pretty. Of course, Dextron-3 is tempting but you must know what you are 'mixing' it with.