By popular request (really, I got quite a few emails about this!...;-), I finally completed my Beogram DC motor restoration video! It demon...
Sunday, May 13, 2018
Beogram 4004 (5526): Restoration of DC Platter Motor
After replacing the incandescent bulbs in the RPM trimmer panel with LEDs it was finally time to restore the DC motor that drives the platter of this Beogram 4004 (5526). This shows the motor extracted from the Beogram:
Restoration of these motors requires infusing the brass sleeve bearings with fresh oil under vacuum. this requires complete disassembly of the motor:
The Oilite brass bearings are the two small donuts on the black pad. I immersed them in motor oil and pulled a vacuum:
Immediately, air bubbles emerged from the bearings as the vacuum drew the air from the empty pores of the Oilite material. This enabled motor oil to penetrate the bearing material, refilling the empty pores. After about 48 hrs the bubbling stopped, indicating that the infusion process was complete. At that point I removed the bearings from the jar:
I reassembled the motor and put it back into the Beogram. Then I installed my BeoloverRPM device to do a 24 hrs RPM stability test:
The BeoloverRPM device is able to log the RPM of the Beogram for extended periods, which is a great way to detect and diagnose RPM stability issues. It is available to other B&O enthusiasts. Just send an email or use the contact form on the right if you are interested. This shows the RPM graph as measured after about 24 hrs:
This is as good as it gets for the Beogram 4004, and we can conclude that this deck is back on track to spin vinyls for another 30 years.