beolover: Beogram 4002 (5513): Full Functional and Cosmetic Restoration and a Test Spin with The Beach Boys

This post describes the full functional and cosmetic restoration of a Beogram 4002 (Type 5513) that I evaluated recently (see here). This shows the fully restored unit:

It is available for purchase at the Beolover Store.

This shows the unit with the panels and platter removed:

When I started to work on this unit I had coincidentally received a batch of new Beolover Carriage Position PCB for Beogram 4002 and 4004 (Types 551x/552x) boards, and I wanted to try one out from this new batch in this Beogram since it had a broken sensor housing. This shows the original PCB still in place:

The replacement is almost plug and play (the two carriage motor leads need to be soldered to the board after installation). This shows the board in place:

The next step was the restoration of the DC platter motor. Like most of them it ran noisily, suggesting that the bearings were dry. This shows the extracted motor:

I disassembled it to get the bearings out for oil infusion. They are the two small donuts on the black pad upfront:

I immersed them in synthetic oil and pulled a vacuum. Immediately, strong bubbling started:

After a few minutes the entire surface of the oil was foamed up:

The bubbles basically are air that is drawn from the empty pores of the Oilite bearing material. While the air gets pulled out, the oil can diffuse into the bearing, essentially refilling it for another tour of duty.

This process usually takes 2-3 days until the bubbling completely stops. So it was time to focus on the other restoration tasks. As usual, I focused first on the floating chassis. It features the arm lowering mechanism on the carriage as well as the carriage translation mechanism. Usually, these mechanical systems suffer from old hardened lubricants and it is a good idea to take everything apart for a good ultrasonic cleaning followed by re-lubricating. This shows everything still in place:

I removed all the moving parts

for cleaning:

I also extracted the solenoid and disassembled it:

This enabled a test of the plunger magnetism with a small ferrous M3 set screw. As in many cases the set screw immediately was attracted to the plunger:

This indicated that it was time to treat the plunger with my tape head de-magnetizer. After the treatment, the set screw was not attracted anymore:

It is important that the plunger is not magnetic since this can cause it to release with a delay, causing the needle dragging across the record when the automatic return at the end of a record is triggered. Not a happy moment when a $800 refurbished cartridge is mounted on the arm!

While the parts were in the ultrasonic bath, I extracted the damper to tonearm linkage. It is located in-between the arm assemblies. You can see it stick out in the picture below from the v-cut in the small metal sheet that is bolted to the counter weight:

In order to get the linkage out for cleaning its pivot point, the sensor arm needs to be removed:

I removed the locking washer and removed the linkage (make sure you do not loose the small spring that is under the locking washer if you try this at home):

Of course the small copper plate that helps the tone arm move laterally when in up position had come loose when I tugged it with my tweezers. I cleaned off the decayed double sided tape and epoxied it back into place:

I also exchanged the incandescent light bulb in the tracking sensor with a Beolover Tracking Sensor LED Light Source (Beogram 4002 and 4004) for enhanced longevity. This shows the original black bulb housing still in place:

I removed it, which revealed the tracking aperture:

This shows the original bulb assembly and the new Beolover part in direct comparison:

The LED is in the same geometric spot as the light bulb filament, which makes this part a direct drop-in replacement. This shows it installed:

In the meantime the ultrasonic cleaner had finished its work and the parts came out in a nice clean way:

When I re-assemble a damper after cleaning I always install a new gasket in the plunger:

This prevents inconsistencies of the arm lowering speed caused by hardened or warped original gaskets. This shows all the parts in place again:

I also installed a new precision machined Beolover Aluminum Carriage Pulley for Beogram 4002 and 4004:

Beolovely! After concluding my work on the floating chassis, I focused on restoring the PCBs. First came the main board. It has two power transistors installed on its solder side. It is best to replace them when the board is still installed. It makes it much easier to place the new devices in the right spot. This shows the original IC1 (usually a TIP120 Darlington), the voltage regulator of the 21V rail, still in place:

I unsoldered it and installed a higher rated TIP102 in its place. Since modern TIP devices in this circuit configuration tend to produce a high-frequent oscillation at their outputs it is a good idea to add a 100nF capacitor (yellowish package in the photo) to ground. It quenches the oscillation:

After also replacing IC4, I removed the board. This shows the component side in original condition:

A detail shot of the "RPM section" consisting of RPM relay and RPM trimmers (to the left):

I replaced all electrolytic capacitors, power transistors, RPM trimmers and relay, as well as the sensor arm transistor:

This shows the RPM section with a new Beolover Siemens Relay Replacement for Beogram 4000, 4002, and 4004 and two 25-turn encapsulated trimmers in place:

Then I removed the keypad cluster and took out the output PCB. This shows it in its original condition:

This board only contains the output relay and its delay circuit as well as the jack that the DIN5 output cable plugs into:

I exchanged the original Siemens relay with a new Beolover Siemens Relay Replacement for Beogram 4000, 4002, and 4004 and installed a new 100uF capacitor for the delay circuit:

I also installed a (red) switch that allows connecting signal and system grounds in case there is a hum. This is especially helpful if the deck is supposed to be connected to a non-B&O receiver via an RCA adapter.

There were still three light bulbs left to be replaced with LED assemblies. Two of the bulbs resided in the RPM panel above the keypad. This shows the panel removed and flipped over:

The bulbs are found under the two covers on one side of the assembly. Removal of the covers reveals the bulbs:

The two small green circuit boards in front of the panel are the Beolover RPM Panel LED Backlights for Beogram 4002 and 4004 (Types 551x/552x). I soldered them in:

These boards solder directly to the solder points of the bulbs. They essentially function as an extension of the original PCB:

The bulb covers can be re-installed after the PCBs are soldered in place:

The last bulb was in the small compartment of the sensor arm. This shows the compartment pulled out a bit together with the Beolover Sensor Arm LED Light Source (Beogram 4002, 4004 and 4000) and its alignment aid:

I removed the bulb and installed the LED board:

Then it was time to clean out the unit from the transport lock bushing fragments strewn around in the enclosure. This unit was a "beautiful" example of such degraded bushings:

I removed the entire floating chassis as well as the original reservoir capacitor:

This shows the empty enclosure (the wood frame was also removed):

This revealed a bunch of fragments from the bushings:

It is important to get rid of all of these fragments since they can get lodged under the floating chassis, which can impair its vibration dampening function. I vacuumed everything out:

At this point I also checked the fuse box. I often find fuses of the wrong type when I restore a Beogram. This one still had the original set of fuses installed:

In my experience these almost 50 years old fuses often have loose end pieces and should be replaced:

I replaced them and then installed a set of new Beolover Transport Lock Bushing Set for Beogram 4000, 4002, and 4004:

These replacement bushings are designed for easy installation. They come in two halves that simoly push in from the bottom

and the top:

This shows one of them together with the lock bolt:

After finishing the installation of the floating chassis I installed a new Beolover Main Reservoir Capacitor for Beogram 4002 and 4004 (Types 551x/552x). The installation starts with inserting the red alignment piece:

Followed by bolting in the capacitor assembly and soldering the leads to it. In this case the Beogram had a single capacitance main capacitor and therefore only the white and black leads needed to be soldered to the respectively labeled solder pads, while the other pads could be ignored:

The next step was replacing the wood plinth. The original one had a damaged front corner. I baked the frame at 250F for an hour and then used a carpet knife for cutting the metal pieces from the wood frame:

After cleaning all the old contact cement from the metal pieces it was time for installing them into a new Beolover Oak Frame for Beogram 4000, 4002, 4004 and 6000 in 4000c style:

This shows the final result:

The original plinth guidance washers were also completely degraded:

I replaced them with a set of new Beolover Plinth Guide Washer Set for Beogram 4000, 4002, and 4004:

This shows one of them installed on the new frame:

Beolovely! After re-installing the rebuilt PCBs I adjusted the bias of the new sensor arm transistor to yield 4V DC at the collector:

Then I moved the trimmer to the component side followed by working on the mechanical adjustments.

First came the tedious 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 square M3 nut and a washer:

This allows locking the tracking weight in place enabling shipping of the unit while maintaining the calibration. Next I adjusted the arm lowering limit that the needle would not hit the platter ribs in case the arm ever lowered onto the platter without a record present (this could for example happen if the photo cell in the sensor would cease to work):

Then it was time for calibrating the tracking weight:

I usually adjust the counterweight in a way that the calibration is accurate around the 1.2g mark on the weight adjustment wheel. Most B&O cartridges expect 1.2g.

Next came the tracking feedback adjustment:

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

I re-assembled the motor and installed it in the Beogram for my usual RPM stability test with the 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 is as good as it gets with original DC platter motors! The slight observed drift is related to ambient temperature changes.

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

In the fast mode it transmits a 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 60 turns of the platter, representing a run time of about 2 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 to 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 of 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 was 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. It should be pointed out that this discussion is pretty academic since humans start typically recognizing frequency fluctuations above the 0.7% threshold, i.e. the RPM fluctuations of this Beogram are well below this threshold, whether the number is 0.05% or 0.1%. This motor is definitely ready for duty again!

Next I replaced the old grimy DIN5 plug

with a nice new all-metal plug sporting gold plated pins:

Beogolden! At this point it was time to replace the worn keypad with a new Beolover reproduction keypad plate and install a Commander Remote Control for Beogram 4002 and 4004:

This shows the original keypad still installed together with the new replacement:

Beolover offers a keypad restoration service. Please, see here. The replacement keypads look very similar to the original ones, but are made with a modern more resilient coating.

While exchanging the keypad it is the perfect moment for also plugging in the remote control hardware:

The Commander allows controlling all functions of the Beogram with an Apple remote (there is also a Beo4 compatible version if so desired). The setup also adds auto-repeat functionality similar to what the later Beogram 8000 and 8002 offer.

The Commander is the ideal addition to any Beogram 4002 or 4004 for protecting the keypad from wear.

This shows the new keypad in place:

Together with the new 4000c style oak frame this looks just very happy! Beolovely!

And then it was finally time for a first test spin with this completely rebuilt Beogram 4002! Since Brian Wilson's passing I am having a bit of a Beach Boys moment and I am listening frequently to one of the few records that I brought over to the US when I emigrated from Germany in the 1990s. It was the 8th record I ever bought (as you can see from the #8 label that I glued to the top left corner of the cover after I bought it back then in Germany). Down memory lane!...;-). This shows this lovely album together with the Beogram:

A perfect combination! Of course I refreshed this album before play by cleaning it ultrasonically with a CleanerVinyl ProXL setup!

While I was playing this new unit to make sure there are no intermittent issues, I finally received a few new hoods from the dksoundparts store in Denmark (Yes! They are available again!...;-).

This shows the original hood:

It is pretty scratched up and definitely needs attention. Replacing it with a new one is the preferred solution since no mater how much one polishes, it will never be like a newly die cast one and there is always some degree of cloudiness left. I used a razor blade to separate the aluminum trim on the sides for accessing the screws:

This shows the liberated hinge together with the new hood and properly labeled aluminum trim:

I bolted the new hood into the hinge:

Then it was time to install the aluminum trim. It is important to center it precisely when glueing it to the hood. I designed 3D printed alignment brackets that make this process easy: