This is a follow up to my recent post about the redesigned Beogram Commander remote control board, which now works in both (DC-motor) Beogr...
Thursday, August 22, 2019
Beogram 4004: Restoration of DC Platter Motor
I recently received a Beogram 4004 DC platter motor from Texas. The motor exhibited the typical shrieking noises when running it from a bench supply at 5V. A clear indication of dry bearings.
This shows the motor as received:
I took the motor apart to get the brass bearings out for oil infusion:
The bearings are the two small donuts on the black pad up front. I immersed them in motor oil and pulled a vacuum. Immediately vigorous bubbling started, indicating thirsty bearings:
After about 48 hours the bubbling stopped (indicating that the bearings were replenished with oil) and I extracted the bearings:
Then I reassembled the motor and installed it in one of my Beogram 4002s for a 24 hrs RPM stability test using the BeoloverRPM device. The BeoloverRPM allows logging the RPM every 10 seconds over extended periods of time. This is the curve I measured:
This result is as good as it gets! This motor is ready for duty again!