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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...

Monday, June 5, 2017

Beogram 4000: Restoration of the Main and Power Supply PCBs

After replacing the reservoir and motor capacitors of the Beogram 4000 that I have on the bench right now, it was time to rebuild the main and power supply PCBs. It is a good idea to replace the RPM relay and the RPM trimmers along with the electrolytic capacitors since they are often corroded. This shows the main PCB in its original condition:
This is a detail show of the old Siemens relay and the RPM trimmers:
And here an impression after replacing the parts:
The Beolover replacement relay is a drop-in assembly that has the same footprint as the original non-standard Siemens design:
It uses a modern encapsulated relay that promises upward of 2 Min switch cycles before failure...that should last for a few extended vinyl listening sessions!...;-).

The remaining task here was to replace the two Ta capacitors on the power supply board. this shows the original:
The two brown-white units on the right side are the 1uF caps that need replacing:
And this concludes the restoration of the electronics. The next step is the rebuild of the motor.







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