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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...

Sunday, November 8, 2015

Beogram 4002 (5513): Installation of a New Output Relay and a GND Switch

While I was testing the Beogram 4002 (5513) that I restored in recent weeks I realized that the output relay once in a while would not open up after the tip touched down, hence, preventing the audio signal from reaching the amplifier. Luckily the relay is the same type that is used for RPM switching in both 4002 and 4000 models. Therefore, I was able to use the breakout board that I recently developed for replacing the RPM relay in a Beogram 4000 with a modern encapsulated SMD signal relay.

While I installed the new relay I took the opportunity to also install a switch on this board that allows to tie signal and system grounds to deal with humming problems if necessary. Depending how the amplifier is setup it can become advantageous to tie the two grounds together to prevent the formation of grounding loops and/or open leads that can introduce ambient EMI into the sensitive phono preamp input. 

This shows the original relay:

And after installing the SMD replacement and the switch: 

This shows the board after installing it in the Beogram and replacing the plug that connects the cable:

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