Beogram 4000: Restoration of the Arm Lowering Mechanism, Replacement of Tracking Sensor Light Bulb with a LED Assembly, and a New Aluminum Pulley

I started working on the Beogram 4000 that recently arrived with a bit of shipping damage. The first order of business was to reconnect the ejected carriage to its linear rod bearings. This shows the carriage turned over:

and this shows the slide rod with the linear bearings that were liberated from the carriage assembly:

I removed the rod to get the bearings out. This shows them from the bottom:

They have a directionality that needs to be kept in mind when pressing them back into the carriage body. I did that with a big adjustable wrench:

After this procedure I was able to reinstall the carriage and start my normal restoration routine, which usually begins with the rebuilding of the arm lowering mechanism. This shows the solenoid and damper assembly with the connecting linkages and springs:

I removed everything

And spread the parts out:

After cleaning and lubricating I re-assembled the assembly and moved on to the next step, which is the restoration of the linkage between damper and tonearm. This linkage is often stuck or moves only reluctantly. This shows the arms from the back:

Two screws hold the sensor arm in place. After their removal the arm can be taken out:

I removed the linkage. As expected it moved with a lot of resistance and it was difficult to remove it from the pin:

After cleaning the pin and putting some fresh synthetic grease on it, I reassembled everything and adjusted the arm parallelism:

All good again in the arm lowering department. On to the tracking sensor light source. I usually replace the original light bulb setup with my 3D printed LED assembly to ensure long term stability. This shows the original setup:

I removed the bulb housing. This revealed the aperture that sits underneath and controls the light that falls on the light sensors below:

As expected the aperture was pushed to the left due to the shipping issues that reoriented the arms to the right. This will be rectified when I adjust the tracking sensor response. I installed one of my LED assemblies:

The final step was to install a new pulley. I use machined aluminum pulleys provided by Nick (I will be happy to get you in touch if you need one - just use the contact form to the right). This shows the new pulley installed:

Beolovely, I'd say! On to restoring the contacts that control the carriage movements, but that is the topic of the next post about this lovely Beogram.