Beogram 4000: Adjusting the Tracking Force and Replacing the Strange Original Front Center Cabinet Guiding Washer

The Beogram 4000 that I just finished up is now running smoothly. I am playing 'Song for My Father' by Horace Silver (unfortunately a reissue, since the original first pressings are unaffordable these days...sigh!!), which is one of my favorite jazz tunes while writing this post.

Before I got here, however, I still had to do a bit of work on this Beogram: Adjusting the tone arm weight and limits. I also replace the strange standard guiding washer that is typically found installed in the front center guiding slot to ensure a straight movement of the plinth when it is pushed back to secure the aluminum panels. Here is a picture of the original washer including the shoulder bolt:

This awkward setup just does not work well, and consequently later Beogram 400x have a much better design based on an eccentric washer shape. I recently designed 3D printed replicas of this design since they often crack in 4002 and 4004 models that are outfitted with plastic versions of it. See this video for their installation. The parts are available via my Shapeways store (five washers are needed to replace all of them).

Here is a picture of the new washer installed together with a new M3 bolt (note the much lower profile of the assembly, which is beneficial when installing the aluminum panels as chafing is avoided):

After this small detail, I did the arm adjustment. Most important are the zero weight and tracking force calibration and the proper adjustment of the arm lowering limit, which can be the final stop gap that keeps the platter from ripping the needle out of the MMC cartridge in case of a failing photosensor or misadjusted sensor bulb. Earlier I posted videos about these two procedures (tracking force calibration, arm lowering limit). Equally important is the improvement of the weight adjustment screw assembly, which I usually upgrade with a M3 nut and washer. This allows to permanently fix the adjustment in place, which is critical for a successful out-of-the-box setup when I send the turntable back to Italy. The original setup with the locking washer is too flimsy, which can result in a change of the calibration during shipment. Here is a picture of the installed nut:

And here the needle on the tracking force gauge at 1g after adjusting everything:

Ah...Horace Silver via a perfectly adjusted 4000 and my Beomaster 6000 4-Channel - perfect pairings!...I am in Beoheaven..;-)

Beogram 4000: New Arrival from Italy

Exciting! Another Beogram 4000 found its way to my bench for a full restoration! TNT brought it over to the US in an amazing three days. I extracted it from the box. It was quite well packed and arrived safely. The exterior of the unit is pretty decent. No damages to the veneer and the hood is absolutely polishable:

The aluminum trim in the back of the hood came off on one side, but that can be fixed with double sided tape. After I opened it up and removed the aluminum plates (which are in dire need of a deep cleaning) I found that the carriage pulley had come off during transport:

Luckily the parts were easily found in the enclosure:

As usual the main key of the control pad extracted itself from the spring that holds it in place. This proves that it is absolutely necessary to tape the keys down for transport. I reinstalled the pad, switched the unit to 110V and plugged it in (keenly watching for potential smoke...;-). Nothing happened, so I pressed 'ON' and the carriage set itself into motion in search for a record. It stopped as expected at the set-down point for 12" vinyls. So far so good. However the solenoid did not engage. I moved the assembly a few times up and down by hand and then tried again, and there was a life sign. Very reluctantly the tone arm lift engaged after a tired motion of the solenoid plunger...

The unit came with the indication that the arm would not lower. It is clear that this unit needs a full clean and rebuild of the solenoid/arm mechanism. Also the solenoid looks strange and may be a non-B&O part. Other than that I found that the RPM switches are oxidized and do not work every time one presses them. The restoration will cure all that. On the good news end a working strobe light can be noted. 

In my opinion one of the intriguing features of the 4000. The position indicator, which is another remarkable design feature, was already broken once and glued back together. This indicates that this unit was in 'expert' hands at some point. The glue job is fairly well, done, though. 

Furthermore, the indicator light bulbs are dead. My SMD LED replacements will fix that for good. All in all I am pretty confident about this project. This Beogram 4000 is a good starting point for a full restoration, which will take it to near-new performance and looks.

Beogram 400x: Cleaning and Re-lubricating the Tone Arm Lift Mechanism

The Beomaster 4002 (5513) that I am currently restoring exhibited the usual issues with the tone arm lift mechanism: The mechanism occasionally failed to lift the arm up in time before the carriage started moving back (scratch & ouch!) to its home position after pressing the 'Stop' button, or at the end of the record. Also, the relay sometimes clicked before the arm was completely lowered. All this pointed towards time-hardened lubricants in the lift mechanism. The cure for this type of behavior is to take the mechanism apart, clean the old lubricants out and re-lubricate it with a suitable grease. I use a silicone grease. This type of grease is well-suited due to its generally non-corrosive behavior, its compatibility with rubber and plastic parts, and its long-term stability.

The restoration process is straight forward, but requires a bit of insight into the mechanism. For this reason I took the opportunity of this restoration to add a short video about the process to my Beogram 400x YouTube playlist. The video also shows how to adjust the arm lowering time to achieve precise coordination with the output relay activation. Here it is: