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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...

Friday, July 3, 2020

Beogram 4002 DC Platter Motor Restoration

I restored another Beogram 4002 DC platter motor for a returning customer. I guess one Beogram is just not enough for a real B&O aficionado!..;-). This shows the motor:
It made the typical dry bearing noises when I bench tested it. I took it apart to get to the bearings:
The bearings are the two small donuts on the black pad. I immersed them in motor oil and pulled a vacuum. Immediately vigorous bubbling started indicating 'thirsty' Oilite bearing material:
After about 2 days the bubbling stopped and I extracted the replenished bearings from the oil:
I put the motor back together and installed it in one of my Beogram 4002s for a 24 hrs RPM stability test with my BeoloverRPM device:
The BeoloverRPM allows logging the RPM in 10s intervals for long periods of time. Perfect for detecting intermittent RPM issues. This is the curve I measured for this motor:
This is pretty much as good as it gets with the DC platter motor! Time to send this motor to its new Beogram home!






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