Beogram 4002 DC Motor Restoration

A Beogram 4002 DC Motor arrived from Virginia. This is the motor as received:

I took it apart to extract the bearings for oil infusion. As with most Beogram DC motors, this motor made squealing noises when I ran it from my bench supply. A clear indication of dry bearings, the most likely root cause for RPM variations. This shows the disassembled motor:

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

Immediately, strong bubbling started from both bearings. This indicates that the vacuum drew the air from the pores of the brass Oilite bearings. After about three days the bubbling stopped, indicating that the infusion process was complete. I extracted the bearings from the oil:

Then I reassembled the motor and installed it in one of my Beogram 4002s for an RPM stability test with my BeoloverRPM device.

This is the 24 hrs RPM curve I measured:

A very nice result. Pretty much as good as it gets with the Beogram 4002 DC motor! This unit is back in business!

1615CMBG4002MOT