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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...

Saturday, April 23, 2016

Beogram 4002 (5513): A Broken Off Solenoid Plunger and New Transport Lock Bushings

Oh well...a sad moment: A Beogram 4002 (5513) that I recently sent back to a customer already returned. A few weeks after a happy report of enjoying vinyls on the newly restored 4002 (via my recently developed internal Beogram RIAA pre-amp) an email reached me stating that the tonearm would not lower anymore. So the deck was packed up again and it came back to my bench. What I found was pretty astonishing:
If you look closely, you see that the solenoid plunger went missing. No surprise that the arm did not lower anymore...nothing to there for pulling the linkage that activates the damper, and with that the arm lowering mechanism. So I went looking for the plunger. After taking out the sub chassis
I finally found it:
The amazing thing here is that the end of the hook that grabs the linkage broke off...I never saw such thing before, but I guess material fatigue can hit the most unlikely places.

The only solution for this issue was to replace the solenoid with a unit from a parts 4002 that I bought on ebay a while ago:
After this implantation the mechanism worked again. While I had the sub-chassis out it became apparent that the transport lock bushings did not survive the return trip and that they needed to be replaced. This shows the detritus of the front lock bushing:
I should have replaced them during the first 'visit' of this Beogram, but they looked o.k. then and so I left them. I think it can be said with some certainty that all orange looking bushings need to be replaced at this point in time. The grey ones seem to survive better.

I replaced all three bushings with my nylon replacement parts printed by Shapeways:
Each bushing is replaced by two of these parts, one goes in from the top and the other one from the bottom:
This shows the left-side lock put back together:
There is a video about installing new transport lock bushings in my Beogram 4002 playlist. The bushings can be ordered directly from my Shapeways store. This is the link to the part. Two are needed per transport lock.

Allright...this Beogram is on the mend. However, before I send it back, I will give the DC motor my oilite bearing oil infusion treatment. When I initially 'rebuilt' the motor of this Beogram, I did not know yet about the necessity of infusing the brass sleeve bearings of the Beogram DC motors with oil under vacuum. This is the only way to re-lubricate the bearings with lasting effect that the motor can serve another 30 years...this is Beolove!

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