Beogram 4002 (5513): Rebuilding the Arm Lowering Mechanism and Linear Tracking System

I started working on the next Beogram 4002 (5513) that I recently received for a restoration. I first rebuilt the arm lowering and tracking mechanisms. They usually need attention due to hardened lubricants and misadjusted tracking sensors. This shows the solenoid-damper set-up before I took it apart:

Here is an impression of the disassembled mechanism for cleaning and lubrication:

  

This video shows how to rebuild the tone arm mechanism in detail. Next I focused on the linkage that connects the damper with the tonearm. It often moves with difficulty due to hardened lubricants:

The photo above shows the back of the arms. The two screws at the bottom right behind the solenoid (yellow) hold the sensor arm in place. I removed these screws and took the sensor arm out for disassembly:

This shows the linkage removed:

This video shows how to get to the damper to arm linkage and re-lubricate it. After putting everything back together I aligned the arms to be perpendicular to the keypad and parallel to each other:

Then it was time to replace the tracking sensor light bulb with my custom designed LED assembly. I always do that since the original bulb assemblies are not available anymore, and the LED based replacement has the potential to last for a very long time, ensuring trouble free operation down the road. This shows the original set-up:

and after replacing the old bulb housing with my replacement part. 

The blue square is a trimmer potentiometer that allows the adjustment of the intensity of the inherent LED. This makes the fine tuning of the tracking response much more straight forward than with the mechanical excenter alone.

Then it was time for Sam River and my dented MMC20EN cartridge from ebay to do the tracking sensor sensitivity adjustment. There is a video that shows the tracking sensor adjustment procedure in detail.

This photo shows the adjustment of the potentiometer after the coarse mechanical adjustment was accomplished:

On to the next task!