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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...

Tuesday, May 7, 2024

Beogram 8000/8002: Redesigned Motor-Capacitor Based on Multilayer Ceramic Capacitors

I recently redesigned my motor capacitor replacement for Beogram 8000 and 8002. The goal was to have a part that can be used in both US and European versions of these turntables.

The motor capacitor is responsible for producing the phase-shifted signal for the secondary motor coil in the linear induction platter motor. This means that for an optimized motor signal different capacitances are necessary if the two phases are to have the same amplitude. B&O employed non-polar 27uF electrolytic capacitors in the 110V/60Hz versions for the US market, while for 50Hz versions 39uF was used.

Using modern ceramic multilayer SMD capacitors it was possible to design a replacement assembly that supports both capacitance values:

I designed two capacitor arrays that comfortably fit onto a small PCB that I bolted to a 3D printed fixture that holds everything neatly in place inside the power brick:

The board simply connects to the two wires that originally connect to the non-polar electrolytic capacitor:

The assembly is installed by connecting one of the two leads from the original motor capacitor to the "COM" pad, and the other wire to the 27uF (60Hz versions) or to the 39uF (50Hz versions) pad. This shows the board implemented in the power brick of a US 110V/60Hz version of a Beogram 8002:
If it were a European 220V/50Hz version, the second wire would be connected to the 39uF labeled terminal instead.
Like most Beolover designs featured on the blog, this part is available for purchase via the Beolover Store

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