Beogram 4000: Restoration of the Arm Lowering and Tracking Systems

I started working on the Beogram 4000 that joined me recently from Germany. As usual, I first rebuilt the tracking and arm lowering mechanisms. This shows the solenoid and damper arrangement that controls the arm lowering:

This shows the area after extracting the components that need cleaning and relubricating:

And these are the parts spread out:

After cleaning and lubricating I put everything back together, and then it was time to take care of the stuck damper-to-arm linkage. This part can only be accessed after removal of the sensor arm. This shows the arms from the back:

The sensor arm can be removed after taking out the two screws that hold it at the bottom:

This shows the arm with the linkage already removed. After lubricating the pivot point I replaced the arm and adjusted both arms to be parallel and orthogonal to the carriage rods:

This Beogram came with loose carriage rod bearings:

The white part on the rod belongs press fit into the bottom of the carriage plate. The second bearing was also loose already, and so I removed it too. Then I put a bit of epoxy on the parts and pressed them back into the carriage base:

After that the carriage was held in place again and I moved on to replacing the light bulb in the tracking sensor with a LED based assembly. This shows the original setup. The back square is the bulb housing:

After removing it the sensor aperture was revealed:

I installed the LED based assembly and also replaced the rusty sheet metal screw that fixed the aperture to the tone arm base with a stainless M2 screw and a nut. This holds the aperture in place much more solidly than the original screw, which often comes loose due to vibrations during transport etc...:

The next step was to replace the cracking prone carriage pulley with a precision machined aluminum pulley provided by Nick (let me know if you wanted one, too, and I will get you in touch!).

This shows the original pulley:

and the replacement:

I just love how they look like! Beolovely!

While I was 'in the area' I also checked on the the carriage position switches. To get to the switch terminals the carriage motor leads need to be unsoldered and two screws removed, and then the board can be lifted up:

I cleaned the contact areas with 2000 grit sand paper and then coated them with a bit of DeoxIT D100 to slow down re-oxidation. On to rebuilding the keypad cluster.