Beogram 4004: DC Platter Motor Restoration

I recently received the DC platter motor of a Beogram 4004 from a customer in Poland for restoration. It exhibited the usual RPM variations due to dry motor bearings.

This shows the motor as extracted from the packaging:

I disassembled the motor to extract the bearings:

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

Immediately strong bubbling started. This is indicative of air being drawn from the empty pores of the Oilite bearing material. This makes room for oil to diffuse into the bearing, replenishing its oil reservoirs.

After about three days the bubbling stopped and I extracted the bearings from the oil:

I reassembled the motor and installed it in one of my Beogram 4002s for a 24 hrs RPM stability test with the BeoloverRPM device:

The BeoloverRPM allows logging the RPM in 10s intervals for extended periods of time, perfect for detecting sporadic RPM fluctuations. Luckily with this motor no significant fluctuations were detected. This is the curve I measured:

A very nice curve! This motor is back in business and can be sent home to its Beogram!