Beogram 4004: Restoration of the DC Platter Motor

I recently received the DC platter motor of a Beogram 4004 from a customer in Minnesota for an oil infusion of its bearings.  

This shows the motor as received:

I disassemble it to get the bearings out:

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

The bubbling represents air being drawn from the porous Oilite bearing material. As the air leaves the material oil can diffuse into it. This process can take up to three days. After the bubbling stopped I extracted the bearings from the vacuum chamber:

Then I re-assembled the motor and installed it in my bench Beogram 4002 for a 24 hrs RPM stability test with my BeoloverRPM device:

In its 'slow' mode the BeoloverRPM is able to log the RPM in 10s intervals into a serial port on any PC. This is the curve I had measured after about 24 hrs:

This graph is about as good as it gets with Beogram DC platter motors after restoration. In my experience the slight choppiness will go away over time as the top bearing settles in. This motor is ready for another tour of duty!