Another Beogram 4002 DC platter motor in need of repair came to my workshop from Virginia. Here’s a picture of the motor:

The motor’s pulley was unusually worn, with a groove where the raised center, designed to keep the belt aligned, should be:

It barely functioned during the initial test. To address this, I disassembled it to lubricate the bearings:

The bearings are the two small rings on the black surface.

An inspection showed that the motor had been previously opened and lubricated. This resulted in oil contamination of the commutator and brushes, explaining the performance issues. Oil tends to spread, leading to the motor’s malfunction. In this case, excess oil from the bottom bearing reached the commutator. I reattached the brush carrier to the enclosure base to safeguard the delicate pickup coil wires and then cleaned the carrier and rotor in a detergent solution:

I then used an ultrasonic cleaner, which created an oil and water mixture:

After removing the parts, they were rinsed with pure isopropyl alcohol to eliminate any remaining water.

The bearings were then soaked in oil within a vacuum environment:

The appearance of bubbles indicated that the oil was penetrating the bearings. This process lasted for approximately two days, after which the bearings were taken out, and any excess oil was removed:

I then reassembled the motor with a new pulley:

The new pulley, a precise reproduction crafted using a CNC machine in Austria, ensures smooth belt operation and is accessible to other B&O enthusiasts. Contact me for details.

Finally, I tested the motor in a 4002 turntable using the BeoloverRPM device, which tracks RPM over time:

The results, recorded after 24 hours, show excellent stability:

This indicates the motor is functioning optimally and ready for use.