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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...

Friday, January 15, 2016

Beogram 4002 (5513): Repair of a Missing Leaf Spring on a Plate Lock

When I set out to do the sub-chassis, platter and tone arm lowering adjustments on the Beogram 4002 (5513) that I am currently rebuilding I realized that the larger aluminum plate was not seating properly with the plinth pushed back. If that happens it is impossible to properly adjust the platter to be flush with the plate.

The plate was wiggling up and down in the back left corner where one of the locks that are supposed to pull the plate down onto the frame when the plinth is moved back did not do its job. The locks accomplish the pull-down with a leaf spring that is attached to the bottom of the lock plate. This shows the right-back lock that still has the leaf spring attached.
I thought a bit about how to fix this, and I know that many Beograms either never had the springs or they fell off at some point and were discarded. In these cases often a tech bent the lock plate to act as a makeshift spring itself. Now in this case since the other three lock plates still had their springs attached, I did not want to bend just one of them. Somehow this did not feel Beoloving enough. So I came up with this fix:
A 3D printed wedge that fits to the bottom of the lock plate:

I glued it to the bottom of the plate using double sided tape. I always try to do things in a reversible way in case someone comes up with a better fix in the future and wants to remove my fix. 
When I put the aluminum plate in and pushed the plinth back, this wedge very satisfyingly pulled the plate down to where it should sit. All good now with this plate lock! No detail to small for my attention! This is Beolove! On to the platter and sub-chassis adjustment.





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