Beogram 4004 Type 5526 - Restoration Project - SyncDrive and Remote Commander Installation

Continuing on from this project's previous post, I needed to install a Beolover SyncDrive platter motor and a Beo4 Remote Commander.

However, there were still some other follow-up tasks like checking the 21V supply voltage (to make sure it doesn't have any noise), adjusting the TR3 collector voltage with the new R26 trimmer, installing a Beolover platter detector lamp replacement, installing Beolover RPM indicator LEDs and running the platter speed calibration.

Here is the 21V measurement check.  The inset oscilloscope screenshot is zoomed in on the 21 V line so I could check the ripple. The measurement looks very good.

Next, I installed a Beolover platter detector lamp module so I could check (and adjust) the platter detection signal with the 1TR6 trimmer I installed (in an earlier post).
Once the 1TR6 trimmer was properly set, I moved it over to the component side of PCB1.

I changed the speed indicator lamps in the Beogram 4004 RPM indicator panel to Beolover LED modules.

Now I could install the SyncDrive platter motor, run its speed calibration and test the platter detection functionality of this Beogram 4004.

SyncDrive speed calibration...

At this point I was able to calibrate the Beogram 4004 record tracking.

I removed the platter belt for this calibration procedure so I could rotate the platter by hand and check the Beogram 4004 servo motor performance when advancing the tonearm.

While this procedure is usually a repetitive adjustment and measure series of steps, I was pleasantly surprised that I was able to lock in the correct setting only using the coarse screw adjustment shown in the picture above.

Usually I get the setting close using the coarse adjustment, then dial in the final setting with the Beogram 4004 eccentric screw adjustment and/or the Beolover tracking lamp trimmer.

Now for a quick check of the platter detection signal and the position sensor run-out groove detection.

The empty platter detector signal looks good.

Previously I had adjusted the position sensor to output 5V when the clear part of the position scale was in front of the detector.  Note that when the blacked out part of the scale is blocking the sensor, the voltage is around 10 V.  Those can be checked and adjusted (using PCB1 trimmer 1R88) without the platter motor if desired.

The last section of the position scale has a series of narrow black bars.  This is so the position sensor will generate a series of pulses that the detection circuit on PCB1 can interpret as the run-out groove of a record. Each run-out pulse adds to the voltage level that capacitor 1C33 charges up to in the detection circuit until the detection threshold is reached. At that point, the run-out detection circuit initiates a stop and return to end the record play.

This picture shows the position scale bars entering the position sensor area. The inset oscilloscope screenshot shows what the run-out sensor signal looks like when the tonearm is moving through the run-out groove.  In this case the run-out detection circuit triggered on the third pulse.
Note: My measurement point here was at the node for 1D41, 1D42, 1C33 and 1R82 on PCB1.

Last, but not least, was to install the Remote Commander...but first, I still had to clean the old oxidation off the Beogram 4004 control panel button contacts.  I applied some Deoxit fluid on the cleaned contacts.

While checking the button panel I discovered that one of the buttons was badly damaged and would not work.  I replaced the plastic button with a spare.

With the button panel restored and tested, I install the Beolover Remote Commander.
This version of the Remote Commander is designed to operate using a Bang & Olufsen Beo4 remote control.

Also...note that the Remote Commander installation is using the Beogram 4004 options.

Using the Beolover Remote Commander with a Bang & Olufsen Beo4 remote control can be a little bit tricky.  That is because the Beo4 remote control is configurable and may not be ready to work with controlling a Beogram right out of the box.

This was the case I ran into with this Beo4.  It did not have the Phono option in its list of supported components.  Adding that to the Beo4 menu list is not difficult but it wasn't intuitively obvious.
Beolover describes the setup in this video.

This Beo4 had one additional wrinkle however.  It did not have a Phono named function in its memory to add to the list of components.  It did have "N. Radio" which, it turns out, is another function name that works as a phono selection.

My next step will be to reassemble the rest of this Beogram 4004 and do some record play testing.

Beogram 4004 Type 5526 - California Project - Completed, Tested and Ready to Ship

This post continues from the last post where the initial power on and start play operations were tested on this Beogram 4004.

Even though most of the functions I tried appeared to work I still needed to finalize moving the new trimmer for the platter sensor circuit to its final position.

Here is the DC voltage check of that platter sensor circuit as measured at the collector of 1TR3.
The new trimmer is adjusted to get 4 VDC at the collector with no platter in place.

That was easy to dial in but when I examined the platter sensor signal with an oscilloscope I could see quite a bit of noise on the signal.  The signal was the expected shape but the noise wasn't expected.

I checked the 21 VDC rail voltage for the circuit and could see noise there as well.

The voltage was good but the noise wasn't.

To remove the unwanted noise on the 21 VDC rail voltage I changed the filtering capacitor I had added to a 10uF value, then remeasured the rail voltage and platter sensor signal.

Much better now.

Even though the sensor circuit appeared to be working correctly, I have seen where noise like I was getting cause strange things with the Beogram control circuit.  

I installed the new Beogram platter speed indicator lamps next.
These are the Beolover LED replacement lamps from the DKaudiolover.com store.

Here are photos of the cleaning and Deoxit treated Beogram control panel contacts.
This Beogram 4004 will be getting the Beolover Remote Commander installed but I want to make sure the manual control button operation is perfect.

This picture shows a couple of contacts cleaned and treated on the left while the other contacts have yet to be cleaned.

...and this picture shows the full set cleaned and treated.

I used the Beolover RPM measurement tool to calibrate the 33.33 and 45 RPM platter speeds of the Beogram 4004.  This Beogram 4004 has a Beolover restored DC platter motor so it must be calibrated to the correct speeds.

Next is the installation of the Beolover Remote Commander (one of my favorite additions to any Beogram 4002 and 4004 turntable).

The installation of the Remote Commander to a Beogram 4004 is slightly different from a Beogram 4002 as the Beogram 4004 has a basic, no-frills remote control circuit that must be tied in to.

A drawback of the built in Beogram 4004 remote control circuit is that it is only functional when the Beogram 4004 is paired with a Beomaster 2400 receiver.  And...the remote control of the Beogram is just play, pause and stop.  The Remote Commander provides all of the Beogram 4004 control panel functions.

Now the Beogram 4004 is ready to be reassembled and some records played on it.

The final step of this restoration project was to replace the original dust cover with a brand new one from DKSoundParts along with a new aluminum trim piece.

The first step is to center the new trim piece and mount the trim onto the top portion of the new dust cover.  The two ends that bend down over the left and right sides are left straight at this point so the dust cover can be mounted onto the metal hinge assembly.

Here is one side of the metal hinge assembly and dust cover attachment screws.

After the dust cover is attached to the metal hinge assembly, the left and right sides of the new aluminum trim can be bent into place.

Note:  This attachment of the trim can be a little tricky. I found that I had to clamp the top and sides in place to make sure the double-sided tape bonded the trim securely (without pulling away).

The new dust cover assembly is now ready for installation on the Beogram 4004 frame.

There are two of these spring loaded mounting clamps that screw down on the dust cover assembly.

I am leaving the protective plastic wrap on the dust cover and Remote Commander remote so the owner of this Beogram can be the first to open them up.

I will listen to a few more records on this Beogram before shipping it back to its owner.

After that, I have another Beogram 4004 to begin restoration on.