Another Surprise Addition To The Workshop Beogram 4004

 Back in 2021 I restored my own personal Beogram 4004 turntable, dubbed the "Workshop Beogram 4004".  That same year I added the Beolover Remote Commander to it and have happily been playing a lot of records with it.

This year I have another surprise addition to my Beogram 4004...a Beolover SyncDrive Platter Motor.

Ever since reading the Beolover Blog announcing the Sync Drive I have been wanting to try it out.

As I mentioned, my Beogram 4004 was already restored and I use it regularly.
The DC platter motor had been restored by Beolover back in 2021 and works great.

However, I love the idea of a self calibrating platter motor that is even more accurate and was ready to try it out in person.

First, I remeasured the original DC platter motor using the Belovover RPM Tool v2.
I wanted to have current values to compare the original platter motor with the SyncDrive.

This screenshot shows the measurements from the Beolover RPM Tool v2 being recorded on a PC.

I ran the measurements for twenty hours.  Of course that is way longer than a platter motor would ever be run in normal use but it has been the length of time we usually collect RPM measurements on the Beolover Blog for comparison.

After saving off the measurement data for the original platter motor (at 33.33 RPM) I switched out the motor with the new Belover SyncDrive.

The changing of the motor is incredibly easy.

Here is the Beolover SyncDrive as received from Beolover.

Here is the connection point to the Beogram 4004 main board.

Here is the SyncDrive installed.

...and turned on by starting the platter turning and pressing one of the SyncDrive control buttons.

The SyncDrive came on showing me that my current settings have a 33.33 RPM value that is a little too fast.  Not surprising since I hadn't run a calibration with the SyncDrive yet.

Here is the Beogram 4004 platter speed measurement with the SyncDrive installed and after it calibrated itself for 33.33 RPM.

How great is that?  So easy.

My favorite features of the SyncDrive are its control buttons.
I love being able to run automatic, self calibration for 33.33 and 45 RPM.

I also really like locking out the original Beogram control panel speed adjustment controls.

Now for the measurement comparison.
Using the Beolover RPM Tool v2, I also measured the 33.33 RPM of the Beogram 4004 platter using SyncDrive.  Again, I ran the measurement for twenty hours.

Looking at the measurement results you can see that both platter motors produce a consistent and controlled platter speed for twenty straight hours.

That is what I expected.  After all, my original DC platter motor was restored by Beolover back in 2021 and should easily last another forty years.

However, you can also see how much tighter the RPM measurement is with the SyncDrive controlling the speed.

Also note that the mean for the original platter motor shows that it had drifted a bit slower than my original setting in 2021.  It measured a mean value of 33.24 RPM.  
The 33 RPM trimmer on the Beogram 4004 main board could be used to readjust that along with a good measurement tool like the Beolover RPM Tool v2.

With the SyncDrive motor that type of readjustment is no longer necessary.  You simply press the Auto Cal. button and two minutes later the platter speed is calibrated and locked in.

With either a Beolover restored DC platter motor or a Beolover SyncDrive, a Beogram 4002/4004 owner can get a beautifully functioning turntable.  I just prefer (and appreciate) the technical achievement and performance of the SyncDrive.

Now back to listening to records.

Beogram 4004 for the Workshop: Surprise addition of the Beolover Commander Remote Control !

Since the last post for this project I successfully ran some listening tests.  This Beogram 4004 plays records beautifully again so I was ready to reattach the deck panels and listen to more records.

However...I received an amazing surprise...a preliminary version of the latest Beolover 4002/4 Commander Remote Control.

On more than one Beogram 4004 restoration project in the past I was asked by people if the restoration could include the Beolover Commander Remote Control.  Unfortunately the answer was no.  The initial version only supported the Beogram 4002 type turntables. That is now changed as this latest version includes support of the Beogram 4004. There was good reason the earlier Commander didn't support the Beogram 4004 and I will talk about that when I show the installation below.

But first, here is this Beogram 4004 with the deck panels and tonearm cover back in place.

If you look at a lot of our other blog posts of Beogram 4002/4004 restoration projects you will see that installing the deck panels includes the tedious task of adjusting the floating chassis springs.  Both the height of the platter and the centering of the platter within the deck opening can require a lot of iterations.  This Beogram was no exception but I was finally satisfied with the result.

Here is a view from the top. It includes the tools I used to get everything aligned.

Now for the special surprise of the Beolover Commander Remote Control.

The Beolover 4002/4 Commander Remote Control comes with a main board component that has the IR receiver attached as well as an LED indicator for the Beogram speed control panel.  The Commander also includes the Beogram 4004 PCB 8 connector adapter and of course the remote control itself.

Here is a closer look.

The Commander came with its board jumpers set for a Beogram 4002.  I moved the three jumpers over to the Beogram 4004 position as that is the mode I will be using the Commander.

To go along with that mode the Beogram 4004 PCB 8 adapter connector is attached to the main Commander board at the connector marked "to 4004 output board".

Now for the installation.

As I mentioned above, the original Beolover 4002 Commander did not support a Beogram 4004 turntable.  The reason is because the Beogram 4004 turntables have a different wiring harness on the button control panel.  The Beogram 4004 PCB 8 output board has an early Bang & Olufsen remote control circuit that is designed to integrate with the remote control system of the Beomaster 2400.  That remote control integration between the Beogram and Beomaster is a wired connection via pins 6 and 7 of the phono DIN connector. 

While the original Beogram 4004 and Beomaster 2400 remote control functionality is nice, it is limited to Play, Stop, Cue Up and Cue Down.  It has no forward or reverse scanning.

The Beolover 4002/4 Commander Remote Control has Play, Stop, Cue Up, Cue Down, Scan Forward, Scan Reverse and Repeat play. The scanning control also supports slow and fast scanning.

The first part of the Commander installation is to insert the Beogram 4004 PCB 8 adapter connector.

The PCB 1 mounting screw shown below will be used to attach the Commander main board to the Beogram 4004 main board.

The Commander main board connector male pins fit into the Beogram 4004 PCB 1 connector for the button control panel.

The Beogram 4004 button control panel connector for PCB 8 now plugs into the Commander adapter.

The other connector of the Beogram 4004 button control panel harness plugs into the connector on the Commander main board.

The small LED board and harness is installed in the Beogram speed indicator panel.

The Commander system is now installed.

The little IR sensor peeks out from under the trim in the front of the Beogram...ready to detect commands from the remote control unit.

But does it work?

Of course.

Very nice. 
Having played around with the remote control functions of the Beomaster 2400/Beogram 4004 system I can say the added capability of the Beolover 4002/4 Commander are quite a welcome addition.  Highly recommended :-).

Beogram 4004 for the Workshop: Measurements & Adjustments

After performing the restoration work on the two boards, PCB 1 and PCB 8 I moved to checking the voltages on 1TR3 collector for the record detection circuit and on 4IC1 collector for the position sensor.
The new 1R26 5MΩ trimmer will be used to set the voltage on the 1TR3 collector to 4 VDC.  The 1R88 trimmer will be used to set the voltage on the 4IC1 collector to 5 VDC (when the sensor is getting its light stimulus through a clear part of the position scale).

Here is the position sensor adjusted.

Here is the record detection circuit adjusted.

Trimmer 1R26 can now be desoldered and soldered in place on the other side of the PCB 1 board.

I will double-check the actual record detection waveform on an oscilloscope later but first...
I need to do some work on the tangential arm assembly.

This Beogram 4004 turntable is in really great condition but I did notice during the assessment checks that the platter motor and the tangential arm servo motor make a lot more noise that normal.

The platter motor being noisy isn't too surprising given that they often are lacking oil in their sintered bearings (self-lubricating bearings). That happens after 30 years.
Whenever I have sent Beolover some Beogram 400x platter motors for restoration I often send along a couple of my own.  That worked out nicely here as I have a nice Beogram 4002/4004 DC platter all nicely restored by Beolover to swap out with this noisy one. Note that this one is marked serial number 1947049. 

Of course the restored DC platter motor is super quiet.  There is still the tangential arm servo motor though.  It was making the most noise.  Especially when the arm was returning to the stop position.

I removed the servo motor from this Beogram and tested it with a bench power supply to see if the motor was still noisy when out of the Beogram chassis.  It definitely was.  Even at slow speed.
The servo motor is sealed and isn't a motor Beolover currently offers a rebuild for so I grabbed a spare servo motor and figured that would be a quick and easy swap.

It turned out not to be the case. The next three servo motors I tried were all too noisy for my liking.
I finally found a nice quiet one from a Beogram 4002 turntable.

Here is a photo of the four noisy servo motors.

Along with the good, quiet, replacement servo motor I installed a new aluminum tangential arm pulley for the Beogram 4004 spindle assembly.

Even though I didn't photograph the spindle cleaning and lubrication I took this opportunity to perform that task as well. I used the same lubricants as I used on my other Beogram 400x restorations.

A mixture of the NUTO H32 and Rocol MTS 2000 is used for the spindle lubrication.
I use the DX Paste Grease for the front tangential arm rail.

The next set of tasks were to get the Beogram 4004 tangential arm assembly checked and adjusted.
- First thing is to set the platter height where the surface of the top platter is 23mm below the top of the fixed arm assembly.
- Second thing is to set the lowering limit of the tonearm so the phono stylus is about 1mm above the lower platter rib section.

- Third is to calibrate the phono cartridge tracking force.

Platter height

Stylus lowering limit

Tracking Force Calibrated
I calibrate the tracking force at the 1 gram position as it is the most commonly used.

I use threadlocking Loctite for the adjustment screws so they can't move during any vibrations the turntable might experience (like transporting).

Now that the tangential arm components are adjusted to their correct positions I can set the tracking sensor sensitivity.

The position sensor, tracking sensor and record detector sensor lamps on this Beogram are all still functioning good so I decided to leave them as is for now. 

Remarkably the tracking sensor was already very close to a proper adjustment. It only required a small tweak of the eccentric adjustment screw to fine tune the setting.  

I reinstalled the platter on the Beogram and adjusted the two speeds using the Beolover RPM tool.

The platter motor silently and easily adjusted for the two speeds.

Now that the platter spins properly I checked the record detection sensor signal when no platter is present.

The record detection circuit is a good solid signal at 33.333 and 45 RPM platter speeds.  The low part of the signal goes all the way to zero volts which is what I am expecting.

Last on the task list for this post is to replace the platter speed indicator lamps with the Beolover LED lamp assemblies. It is always worth mentioning that these lamps are part of the Beogram platter speed control circuit and do affect that performance.  Beolover has measured an increased stability in the platter speed control with these LED assemblies over the original incandescent lamps.  The Beolover LED assembly is designed to work with the speed control circuit the same as the incandescent lamp but without changes due to lamps heating up.

Here is the Beogram 4004 speed indicator panel.

Here is a look at one of the Beolover Beogram 4002/4004 indicator lamp assemblies. 
They come as a set of two (left sided mount and right sided mount).

The LED lamp assemblies are soldered in place and some included double-sided tape helps secure the small boards to the panel.

The speed indicator board is complete and ready to reinstall.

This Beogram 4004 is ready to start playing some records.