Beogram 4002: Restoration of DC Platter Motor

I recently received a Beogram 4002 DC platter motor from a customer in France for restoration. His Beogram had the usual randomly occurring RPM variations. Something that will most likely be fixed by re-infusing the dry motor shaft bearings with oil under vacuum. Most of these motors have bearings that lost all of their stored oil, and this causes the shaft friction to increase significantly.

This shows the motor as received:

I disassembled it to extract the shaft bearings:

The bearings are the two small donuts upfront on the black pad. I submerged them in synthetic oil and pulled a vacuum. Immediately, strong bubbling started around the bearings:

The bubbling indicates that air is being drawn from the pores of the Oilite-bearing material. The leaving air is successively supplanted by oil in a diffusion process. The process has completed when the bubbling stops. In this case, this happened after about two days. At that point, I extracted the bearings from the vacuum chamber:

Then I reassembled the motor with a new Beolover DC Platter Motor Pulley for Beogram 4002 and 4004 and installed it in my bench Beogram 4002 for testing with the BeoloverRPM device:

The BeoloverRPM is able to log the RPM in 10s intervals into a serial port of a computer over long periods of time. This allows precise detection of intermittent RPM deviations that otherwise would be difficult to detect. This is the graph I measured after about 24 hrs:

This flat curve is 'as good as it gets' with Beogram DC platter motors! This motor is ready for duty again! It is time to send this motor home to France for another tour of duty in its Beogram 4002!