This is a walk-through through the insides of a Grado Laboratory Standard Turntable (1964).

Note: the small circlip that supports the record platter has holes that are 0.042 inches in diameter, so you will need a very fine-tipped set of retaining ring pliers to remove it (if you plan to use retaining ring pliers to remove the circlip).

The belt that was on this turntable when I received it was very loose (likely stretched), and measured about 0.186 inches in width and about 36.5 inches in length. I replaced the belt with Russell Industries part no. PRX35.1, which is 0.184 inches in width and 35.1 inches in length. Thee 35.1 inch belt is a bit tight (and the platter does not want to self-start rotating) but the platter rpm is much closer to 33 1/3 (the original belt caused it to turn slow by ~3%).

The platter bearing nut uses a 1'' socket. The platter fixing plate bolts use a 7/16'' socket.

The motor mounting grommets have been replaced with part no. RGR1814 (SBR rubber, hardness 55A; i.d. 1/8''; for hole dia. 1/4''; panel thickness 1/16''; overall thickness 7/32''; overall o.d. 11/32'').