With that in mind, I'm keen to learn which lubricant is appropriate for my Studer machine.
As I said, it depends what you are trying to lubricate and why you feel the need. Using the wrong form of lubricant will knacker the motor completely, and if you over-do it you'll get oily leaks making a mess of everything and potentially upsetting the electronics.
The capstan motors of all Studer machines use a sintered bearing which is saturated with lubricant using a vacuum process during manufacture. This is intended to last the entire life of the motor and can not be replaced 'in the field'. Indication of needing re-lubrication includes significantly degraded wow and flutter, failure to maintain steady speed, or siezing up!
Studer's general policy was to return the faulty motor to the factory for refurbishment and install a new replacement, but I have seen service reports that suggest in-field re-oiling is possible for temporary work-arounds. the motors do have a finite life, though, and sooner or later it will need to be replaced.
Most Studer motors have a label on them to say what lubricant is used. The earlier motor designs used a synthetic ester-oil -- Isoflex PDP65 synthetic oil -- re-oiling can be achieved by applying a few drops -- and only a few drops -- to the felt ring around the top of the capstan motor shaft (under a plastic cap).
The later 'liquid grease' versions should have a red label on the bottom. I'm pretty sure the A807 uses the later generation of motors which are lubricated with liquid grease in the form of Constant GLY2100. Getting at the capstan motor in an A807 requires removal of the headblock, after which you can remove the plastic dust cap at the top of the motor and apply a few drops of the appropriate liquid grease. Again, don't over do it!
Technical Editor, Sound On Sound