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Beolover SyncDrive: DC Platter Motor Replacement for Beogram 4002 and 4004 (Type 551x and 552x)

Late Beogram 4002 and the 4004 (Types 551x and 552x), which have DC platter motors instead of the earlier synchronous AC motors usually suff...

Thursday, June 2, 2022

Beogram 4002: DC Platter Motor Restoration

I recently received a DC platter motor out of a Beogram 4002 located in Virginia. This shows the motor as received:

I disassembled the motor to get the bearings out for oil infusion:
I submerged the bearings in motor oil and pulled a vacuum:
Immediately vigorous bubbling started from the bearings. This indicates that the vacuum drew the air from the empty pores of the oilite bearing material. This made room for fresh oil to inter diffuse into the bearing. After about 3 days the bubbling stopped and I extracted the bearings from the oil:
I installed them back in the motor. Then I tested the reassembled motor in one of my Beograms with the BeoloverRPM device, which allows logging the RPM in 10s intervals over extended periods of time:
This is the curve I measured after 24 hrs:
This is as good as it gets with Beogram 4002 DC platter motors! This motor is ready for duty again!


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