Beogram 4002 (5513): Full Restoration and Upgrade with New Carriage Motor and Commander Remote Control

This post documents the full restoration of a Beogram 4002 (Type 5513 with DC platter motor) sent in by a customer from California. See here for my initial assessment of this unit. This unit also received two upgrades: a Beolover Commander remote control and a new Beolover carriage motor. This photo shows the finished result of the restoration:

This Beogram looks almost like new again!

Let's take a look at what it took to get there! This shows the unit right after arrival with the platter and aluminum panels removed on the bench:

As usual with the DC motor Beograms, I began my work by removing the platter motor. Most need their Oilite bearings re-infused with oil under vacuum. This shows the removed motor:

The upside-down installed pulley indicated that this motor had been worked on before. This was confirmed by alignment scratches and black marks on the inner motor housing:

A check of the pickup coil resistance indicated that the coils were undamaged, so I proceeded with my disassembly efforts. A lot of motor repair attempts end with broken pickup coil wiring, and it is often difficult to recover if that happens.

All parts inside the motor were oily. Clearly, someone had opened it and messed about. If oil gets on the commutator and brushes, these motors usually run very erratically. I tried this out personally in the distant past when I opened my first motor trying to fix it...;-). Now, more than 200 motors later, I learned a few things. One of them is that oil needs to be limited to the Oilite bearings. The rest must remain dry.

I put the parts into isopropanol and then ran them for 30 min in my ultrasonic cleaner to remove the oil:

This shows the individual parts spread out. The shaft bearings are the two small donuts on the black pad upfront:

I immersed them in synthetic oil

and pulled a vacuum. Immediately, strong bubbling started:

The bubbling represents air being drawn from the pores of the Oilite material. As the air leaves, oil can diffuse into the pores and refill them with oil. Once the bubbling stops, the infusion process is complete. This can take up to three days.

While the bearings were infusing, I started working on restoring the arm lowering assembly and carriage drive mechanics. This shows the original setup:

Someone had made a mess with some black paint on the damper and other parts:

I removed the entire mechanism for ultrasonic cleaning and fresh lubrication:

I also removed the solenoid:

These solenoids often end up with magnetized plungers after decades of cycling the arm lowering mechanism. I pulled out the plunger for demagnetizing:

This particular one was definitely magnetized: It easily attracted a small steel setscrew:

I treated it with my tape head demagnetizer until it would no longer attract the screw:

This is an essential step for every Beogram overhaul. A magnetized plunger often causes sluggish arm lifting during the auto return cycle at the end of the runout groove. Not a pleasant sight when an expensive cartridge drags across the vinyl for several inches before finally lifting off the record!

While the mechanical parts ran in the ultrasonic bath, I turned my attention to the circuit boards. The main PCB features two power Darlington transistors mounted on the trace side. Here is 1IC1, which regulates the main 21V supply rail. Factory installations typically use a TIP120:

I swapped it out for a TIP102, which provides better current handling:

I also added a 100nF ceramic cap (yellow) across its emitter and a convenient ground pad nearby. That capacitor prevents high-frequency oscillations that often crop up with modern replacement TIP transistors in this configuration. After swapping the second bottom-mounted transistor, 1IC4, for a TIP107,

I pulled the board out to access the component side. This shows the PCB in its original condition:

Here is a close-up of the RPM circuitry, showing the original Siemens relay and the two trimmers to its left used for adjusting the platter speeds:

I replaced every electrolytic capacitor, the power transistors, the RPM relay, and the sensor transistor with fresh components. The old RPM pots were swapped for modern 25-turn enclosed trimmers. This shows the finished board:

Here is a detailed look at the newly rebuilt RPM stage:

Next, I pulled the keypad assembly to get to the audio output PCB mounted underneath it. This shows the extracted board:

This board carries the muting relay and its timing circuit:

I replaced the relay along with its electrolytic capacitor, and also added a miniature (red) slide switch to tie signal and chassis grounds together. Connecting the grounds is usually helpful if there is a hum when connecting the Beogram to an audio system:

With the keypad out, I also replaced the indicator lamps in the RPM adjustment panel above it. Here is the removed panel turned over:

Taking off the lamp housings exposed the original bulbs:

The small green boards in front of the panel are the Beolover RPM Panel LED Backlights for Beogram 4002 and 4004 (Types 551x/552x). I unsoldered the old bulbs and installed the replacement LED modules:

They solder straight onto the original lamp pads and essentially form an extension of the existing circuit board:

The plastic lamp covers fit back into place over the LED boards:

It was time to put the carriage back together: Here are the clean pieces out of the ultrasonic bath:

It is a good idea to install a fresh damper gasket:

Fitting a new gasket is crucial because the arm descent rate depends entirely on it. Original rubber gaskets become hardened or warped over time, which leads to sudden drops without proper damping. Definitely not something you want happening to a $600 stylus, hitting the record surface at high speed!

Like so many of these decks, this 4002 arrived with a broken spindle nut bracket. This photo compares the original cracked white plastic piece with the new Beolover replacement part:

Here it is secured in position with the original screw:

My customer opted for the Beolover Carriage Motor for Beogram 4000, 4002, and 4004 upgrade. This shows the new motor next to the removed motor housing with the original motor in it:

I opened the enclosure, which revealed the original motor wrapped in decaying foam:

I removed the original motor and installed the new motor with its vibration-damping EPDM rings:

This shows the installed assembly together with the new Beolover Aluminum Carriage Pulley for Beogram 4002 and 4004 and new belt:

Beolovely! I reassembled all remaining carriage hardware. This shows the completed carriage assembly:

The next item on the list was replacing the tracking sensor bulb. Here is the original black plastic lamp housing in place:

Taking off the bulb housing revealed the optical tracking aperture:

This photo shows the new Beolover Tracking Sensor LED Light Source (red) sitting next to the factory incandescent lamp assembly:

The LED sits in the position of the original filament. Here is the finished LED unit bolted in:

The last restoration task on the arm assembly was cleaning and relubricating the pivot for the damper arm linkage, positioned right between the tonearm and sensor arm. It pokes through the V-notch on the small bracket attached to the counterweight:

I took out the two retaining screws holding the sensor arm base. Then I lifted out the arm assembly:

On this deck, old hardened lubricants had locked onto the pivot rod tightly enough that the pin pulled straight out of its base as I lifted the lever:

I secured the cleaned rod back into its mounting block with a drop of epoxy, then reinstalled the linkage with fresh synthetic lubricant. The remaining epoxy was used to re-secure the small square copper sliding plate that aids lateral arm movement while raised:

Next, I tackled the fourth and final incandescent bulb inside the sensor arm. Here is the small black sensor housing pulled forward:

Beside it sits the Beolover Sensor Arm LED Light Source with its alignment guide, ready to go in. Here it is installed:

That wrapped up work on the carriage assembly.

At this point, most components had already been removed from the enclosure. I also removed the floating chassis so I could vacuum out the remaining crumbled pieces of the old transport lock bushings. Getting these fragments out is essential so they do not jam the floating suspension. This photo shows the cleaned-out enclosure:

It was time to reassemble everything. I put in a fresh Beolover Transport Lock Bushing Set for Beogram 4000, 4002, and 4004:

Each bushing consists of two interlocking halves, which makes installing them straightforward. You slip the lower half in from underneath

and add the second half in from the top:

It is interesting to note that some transport lock orifices have slightly larger holes. Adding a tiny dab of superglue gel along the vertical edges ensures the halves stay seated. With the transport hardware back together, I installed a Beolover Main Reservoir Capacitor module. This shows the original setup:

This 4002 featured the 'dual capacitance' setup, which is evident from the ground wiring attached to the bottom end of the can. The Beolover Main Reservoir Capacitor for Beogram 4002 and 4004 (Types 551x/552x) can accommodate both single- and dual-capacitance setups. Simply connect the wires according to the color labels on the board:

The small round rectifier bolted to the original capacitor assembly 

can be discarded together with the capacitor. The Beolover replacement has a rectifier onboard.

Next, I adjusted the optical sensor bias on transistor 1TR3 using a 25-turn 5MOhm trimmer installed in place of fixed resistor 1R26. The trimmer is initially soldered on the solder side so it can be adjusted with the deck powered up. I adjusted the trimmer until the collector settled at the target 4.0V:

Once dialed in, I shifted the trimmer over to the component side, tucking it neatly behind the replacement 1TR3 transistor (replacing these transistors is wise since the aged parts often lose gain and cause erratic record detection):

Whenever servicing or replacing detection components, measuring the sensor signal is strongly recommended. Here is the waveform on the 1TR3 collector while turning the empty platter:

Every downward dip represents a black platter rib rotating past the sensor. Seeing over 6V peak-to-peak confirms excellent optical contrast. This record sensor is ready for duty!

Then it was time to put the DC platter motor back together and test its performance. The bubbling around the bearings had stopped in the vacuum chamber, and I extracted the bearings from the oil:

I installed the reassembled motor in the Beogram and set up my BeoloverRPM device:

The BeoloverRPM has two operational modes. In 'slow' mode, it measures the RPM in 10 sec intervals and relays the measurement to a serial port of a computer. This allows graphing the RPM over long periods of time using Excel or similar software. This shows the result of a 24 hrs measurement:

This curve shows some slight choppiness. In my experience, this goes away after the motor runs a hundred hours or so. This has to do with the fact that the shaft polishes the bearing in the direction of the platter belt pull, and this improves the performance over time. After restoration, it is possible that the bearing is off by a few degrees, and the polishing process is 'restarted' for the new orientation. I usually mark the bearings before I take them out, but it is difficult to get it 100% during reinstallation. Also, when motors have been opened before I get them (like this one), all bets are off since the bearing position may be completely off. 

I also measured this Beogram in the 'fast' mode of the BeoloverRPM:

In the fast mode, it transmits an RPM measurement every time a platter rib passes under the sensor. This yields high-resolution graphs that show short-term RPM changes ("wow and flutter") in detail. This graph shows a measurement covering about 35 turns of the platter, representing a run time of about 1 min.

The zig-zag pattern is a measurement artifact that comes from the fact that the spacing of the platter ribs around the platter is slightly irregular due to manufacturing imperfections. This generates a repeating pattern every 24 measurements (there are 24 ribs around the platter), which is superimposed on the real RPM changes that are introduced by the feedback system that keeps the motor RPM stable over time. This real RPM change is essentially the sine-wave-like pattern that modulates the zig-zag pattern. An evaluation of the wavy component yields a wow and flutter estimate of about 0.1%. This is 2x the 0.05% stated in the specs list in the service manual.

    This difference is most likely systematic due to the entirely different way wow and flutter were measured in the 1970s when these turntables were produced. Back then, the measurement was carried out with a 1 kHz tone on a test record. In these measurements, deviations from the 1kHz center were measured with an analog spectrum analyzer and then converted into a wow and flutter number.

At any rate, this discussion is pretty academic since the RPM fluctuations (~0.1%) are much smaller than what the human ear can discern (~0.7%). This Beogram platter motor is ready for duty again!

This Beogram was nearing completion, and this was the moment to transfer the metal parts from the original damaged rosewood plinth to the new CNC-machined teak frame. 

I baked the original frame at 250F for half an hour and then used a carpenter knife to cut through the weakened glue to remove the metal parts:

After removal, there is a lot of hardened old glue on the parts:

This glue is pretty difficult to remove. Over the years, I came to realize that alcohol can weaken it substantially over a few days. Previously, I always wrapped the parts in isopropyl alcohol-soaked paper towels. This time I thought it would be nice to fully submerge them in alcohol for a more homogeneous effect. Since I did not have a large enough tray, I resorted to putting the parts into a large Ziploc bag filled with 16 oz of isopropyl alcohol. To get everything soaked with alcohol, I used a small vacuum cleaner nozzle to suck out the air from the Ziploc bag until all surfaces were fully immersed in alcohol:

I let this sit for three days. When I removed the parts, the glue was easily removed with a plastic razor blade:

Beoclean!...;-).

The next step was adding 3M 300 LSE tape and cutting it precisely to match the shape of the metal parts:

Then it was time to install the metal parts on the new frame:

I always use two small Beogram aluminum panels to guide the parts into the right spot. The panels have just the right thickness. I use a strip of baking paper to keep the sticky sides from sticking 

until I guide the front part into the right spot:

Then I pull out the backing paper and press the side part onto the frame. This shows the other side metal frame glued in the same way:

Beolovely! 

The next step was installing the new rebuilt keypad. This shows the original (left) keypad with finger smudges and the new keypad in comparison:

While the keypad was out, it was the perfect moment to install the Commander remote control board. It plugs directly into the keypad header on the main PCB

This shows the new keypad bolted in next to the Commander board. 

See here if you would like to restore your own keypad or send it in for restoration. A perfect-looking keypad significantly enhances the overall appearance and value of any Beogram!

Next, I replaced the two makeshift felt 'feet' that were stuck to the bottom of the enclosure

 with two original plastic feet that I found in my stash:

It is important that the Beogram sits level before the platter position and level can be adjusted. So it needs four equally high feet.

Next, I cleaned up the black mess on the platter bearing assembly:

I soaked the parts in paint remover for half an hour, followed by a good ultrasonic clean:

At this point, I thought I was ready to do the mechanical adjustments of the sub-chassis and the platter, but a little detour to cleaning the cables of this Beogram made me realize that a rodent had gotten to the power cable, exposing some copper:

This was clearly unsafe, and I had to install a new power cord. I usually buy a generic NEMA 1-15P to IEC C7 10ft two-prong power cord and cut off the C7 to match the length of the original B&O cord. Installation required removing the fuses assembly since the cord connects under the fuses. This shows the transformer and fuses box:

The power cord comes in through the feedthrough in front of the transformer, secured in place by a cable gland. Removal of four screws from the bottom of the enclosure liberates the parts:

After taking off the bottom part of the fuses box, the wiring connections are revealed:

The grey power cord wires poke through to the fuses compartment and connect to one side of the fuses:

The other side of the fuses connect to the transformer via the yellow shrouded wiring.

I unsoldered the grey wires

 

and removed the cable gland so I could pull out the damaged original cable:

Then I pulled the new cable through and soldered it to the fuse holders:

It is a good idea to leave the fuses in place for this operation since the fuse holder clips are attached to the central plastic wall of the fuse box, and when they heat up, they briefly get a bit loose when the plastic warms up. The fuses hold everything in the right position until the temperature goes down again.

After soldering, the wiring needs to be routed through the exit opening in the assembly 

followed by installing the lid:

The next step was bolting the fuse box back to the enclosure bottom:

Now the transformer could be bolted back in, followed by routing the new cable around it to the feedthrough:

I usually put in the larger part of the gland to determine where it needs to be placed. I marked that position with a bit of blue tape:

Then I pulled the cable out and pressed the gland onto the cable with strong tongue-and-groove pliers:

Then I pressed the installed gland into the feedthrough orifice

and removed the blue tape:

This Beogram was again safe to be plugged into an outlet!

It was finally time to do the mechanical adjustments! First came the process of aligning arms, platter, and floating chassis to get the platter parallel to the arms across their travel and the platter flush with the surrounding aluminum panels. This can be an iterative process that takes a few passes to yield proper alignment. Once this is completed, the arm adjustments can be done. I usually replace the flimsy locking washer that holds the counterweight screw in place

with a standard M3 square nut and washer:

This locks the counterweight adjustment in place so calibration holds firm during shipping. Before calibrating the tracking weight, I adjusted the arm lowering limit:

The tip should stop about 1 mm above the recesses in the platter ribs as pictured. Next, I adjusted the counterweight using a digital gauge to read precisely 1.2g with the weight dial set to 1.2g:

Next came calibrating the tracking feedback:

With that, the deck was almost ready for a test spin. All that remained was replacing the old RCA plugs

with new shielded all-metal types featuring gold-plated terminals. I added color-coded 3D-printed plastic inserts to indicate right (red) and left (black) channels:

These inserts also serve to center the smaller-diameter 1970s-style B&O wires in the huge exit orifices of the modern plugs, obviously designed to be mounted on 'monster cables' as they are popular these days.

Beolovely! Time for a test spin! I selected an early album by The Who from 1966, which I bought in Germany around 1977 (Polydor 2383 137) as one of my first vinyl records. This has always been one of my favorite records, and it managed to survive the multiple moves I had to make during my life. Here it is playing on this perfectly restored Beogram 4002:

The deck played perfectly without a hitch!

The final assignment was swapping out the badly scratched original dust cover for a new reproduction plexiglass hood. I started by removing the old cover, using a razor blade to release the aluminum trim along the sides of the hood. That allowed access to the screws:

This hood already started getting the usual cracks around the mounting holes:

It would soon have broken off the hinge if left unattended. Here is a picture of the replacement plexiglass hood, fresh aluminum trim, and the removed hinge mechanism:

Before final assembly, I always check for interference between the metal hinge and the plexiglass throughout its open-and-close swing. In this case, there was no interference and the metal part never touched the plexiglass:

With enough clearance confirmed, I proceeded with the installation. 

There is a minor 'quirk' with these reproduction hoods: the plexiglass features a small channel right where the aluminum trim wraps around the side corners, leaving a hollow gap beneath the metal. This makes it difficult to bend the aluminum trim precisely down the sides. To support the bend, I usually glue small 3D-printed filler blocks into the top part of the channel with epoxy:

After the epoxy cures, I slice the excess flush with a razor so the surface matches the edge perfectly:

The next step was centering the trim strip using my (orange) alignment pieces.

A small piece of blue tape allowed me to make an alignment mark:

Next, I mounted the hinge assembly to the hood. I added a bit of white wood glue into the threaded screw holes to stop the screws from coming loose. They cannot be tightened very much since excessive torque will crack the plexiglass over time.

Finally, I glued in the aluminum trim and used my bending block to bend the trim down on both sides:

Here are a couple of pictures of the result:

Here is the completed dust cover assembly with the surface protection film still attached:

I installed the new cover on the turntable and carried it over to my photo studio. Here are a bunch of nice pictures of this perfectly restored Beogram 4002! Enjoy!