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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, January 16, 2017

Beogram 4000: Gold-Plating of the Carriage Position Switch Terminals

The next step of my Beogram 4000 restoration was to electroplate the carriage position switch terminals with gold. In my experience 90% of all operational trouble with this B&O design comes from oxidized switch terminals. These switches present the digital control system with the necessary inputs about the carriage status and if they malfunction, the control system gets thoroughly confused. So my recommendation is gold-plating of the switch terminals. Gold does not oxidize easily and therefore this will result in significant long-term reliability improvements. This shows the carriage switches as I found them:
Not too bad compared to what I found before in other Beogram 4000s, but definitely some black spots indicating oxidation. I removed the terminals:
The oxidized contact points are clearly visible. I cleaned and gold plated them:
And soldered them back into the circuit board:
the next step is to do the same for the switches in the keypad.




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