Beogram 4002 (5523): Adjustment of Platter and Sub-Chassis Alignment, Installation of New Transport Lock Bushings and Adjustment of the Tonearm

After restoring all mechanical and electronic functions of the Beogram 4002 (5523) that I am currently working on it was time to give this baby a spin, and for that I wanted to have platter, sub-chassis and tonearm perfectly aligned to specifications. I started out by aligning the sub-chassis to be in the center of the transport locks. It turned out that a previous 'specialist' had installed the transport locks in a wrong way by not aligning the 'feet' of the lower locknuts with the matching cavities in the cast enclosure bottom. This prevented me from doing the adjustment. While I had everything apart I also put in new bushings since the original ones were completely deteriorated as indicated by the many pieces of orange plastic debris throughout the enclosure:

This shows the left lock with missing bushing:

This shows the new bushings installed in the left transport lock:

and here in the front lock:

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 since one half is installed from the top and the other from the bottom.

After rebuilding the locks I was able to do the adjustments. There are two videos on my YouTube channel that show how to adjust the platter bearing and the subchassis (in a Beogram 4000, but the process is very similar in the 4002). This shows the Beogram after the procedure. The platter is flush with the surrounding aluminum panels and the platter is also centered within the main panel.

The final step was to adjust the arm lowering limits and then the tracking force. There is another video on my youTube channel that shows how to adjust the lowering limits. This is a very important procedure since the control system of the 4002 cannot guard against photosensor failure in the sensor arm. If the sensor fails the arm will be lowered whether there is a record or not, possibly endangering a very expensive cartridge. The correct adjustment of the arm lowering limit can prevent stylus failure if that happens.

The final step is always to adjust the tracking force to specifications. There is yet another video that shows this process. Here are a couple of impressions. I always start out by replacing the flimsy locking washer that holds the counterweight adjustment screw in the back of the arm assembly with a M3 nut and a washer. The original setup is way too wiggly for my taste and virtually guarantees that the adjustment changes whenever the turntable is moved. Not good for shipping at all. This shows the original setup:

and here after installing the nut and the washer:

this allows to reliably lock the zero force adjustment in place, which results in a stable weight scale reading on the small adjustment wheel.

After putting in the nut I adjusted the counter weight to yield 1g when the adjustment wheel is adjusted to 1g. This is better than adjusting the weight to yield zero for zero setting, since the adjustment wheel is not fully linear in its scale. Since most cartridges are in the 1-1.25 g tracking weight range, it is good to use 1g or 1.2g as center point for the calibration.

Then it was time to adjust the final setting with my B&O tracking force gauge:

and then it was finally time for some bliss: Playing one of my favorite records on this deck: Yellow Fields by Eberhart Weber on ECM.