Beogram 4002 DC Motor Restoration

I recently received a Beogram 4002 DC platter motor from Switzerland. I was told this motor had already been opened and the bearings infused with oil, and that, after re-assembly, the motor ran much too fast. This is usually the result if one or both of the feedback RPM pickup coils get disconnected during motor dis/assembly. If this happens, the motor control circuit does not get any feedback, making it 'think' that the motor needs to be accelerated. Hence the full speed. This shows the motor as received:

I opened it up and immediately saw the bent brushes

This sometimes happens when re-inserting the rotor back into the housing after working on the bearings. I decided to do the 'full program' to ensure that the bearings were really fully oil infused etc...This shows the motor disassembled:

The bearings are the two small donuts on the black pad. I immersed them in oil and pulled a vacuum, and indeed almost no bubbling occurred, an indication that the bearings were full of oil. So far so good. I left the bearings in the oil for 24 hrs anyway to make sure. Then it was time to put the motor back together. I identified the issue causing the high RPM: A broken off wire that disconnected the feedback coils:

I reattached the wire:

and straightened the brushes as good as possible:

Then I measured the resistance across the two pickup coils to verify that my repair was successful:

A value between ~35 and 45 Ohms between the red and white leads is normal for these coils. I put the motor back together and installed it in one of my Beogram 4002s for an RPM stability test with the BeoloverRPM device:

The BeoloverRPM allows logging the RPM for extended periods of time in 10s intervals. This is the curve I measured within 24 hrs:

This result is pretty good, but not perfect. In my experience, motors that went a bit through a rough patch like this one need some 'burn in' after they are being put back together that the brushes and the commutator as well as the shaft and the top bearing can get used to each other again. I expect that this motor will be fully quiet after a couple hundred hours of playtime. At any rate the small observed fluctuations are much too small to be audible. This motor is ready for duty again.