Beogram 4004: Restoration of PCBs, DC Platter Motor and RPM Panel

I recently received the PCBs, the DC platter motor and the RPM panel from a Beogram 4004 for restoration. As usual I started with the platter motor since it can take a few days until the oil infusion of the bearings is complete. This shows the motor as received:

I disassembled the motor to extract the bearings:

The bearings are the two small donuts on the black pad upfront. I immersed them into synthetic oil and pulled a vacuum. Immediately strong bubbling started:

This bubbling represents air that is drawn from the empty pores of the Oilite bearing material, making room for oil to diffuse into the material.

While this process was going on, I focused on the other tasks of this project. First I restored the main PCB. This shows it in its original condition:

Here a close up shot of the RPM section consisting of a National brand RPM relay and the two RPM trimmers to its left:

I replaced all electrolytic capacitors, power transistors of the H-bridge and platter motor control and the RPM relay and trimmers:

This shows the rebuilt RPM section with a new Beolover National Relay Replacement for Beogram 4002 and 4004 and two encapsulated 25-turn 5kOhm RPM trimmers:

Next came the output PCB:

In the Beogram 4004 this PCB carries both the output relay delay circuit as well as the remote control circuitry that allows a Beomaster 2400 controlling start and stop of the Beogram via its remote control.

This shows the output relay circuit:

I replaced all the electrolytic capacitors and the output relay:

Here a detail shot of the output relay:

I also installed a (red) switch that allows connecting system and signal grounds in case there is a hum in the output signal.

Finally, I updated the RPM panel with LEDs. This shows the panel on its back which reveals the two bulb covers:

I removed the covers

and replaced the bulbs with Beolover RPM Panel LED Backlights for Beogram 4002 and 4004 (Types 551x/552x):

These little PCBs solder directly to the terminals where the original bulbs connected. They essentially become extensions of the original PCB:

The boards do not interfere with the bulb covers, which can be installed like before:

Now it was time to implant all the components into my bench Beogram. After bolting in the main PCB I replaced the two power Darlingtons mounted on the solder side of this board. It is best to replace these while the board is bolted in. This makes positioning a snap. This shows the original IC1, a TIP120, which is responsible for regulating the 21V rail:

I usually replace these ICs with stronger types. In this case a TIP102 is the perfect replacement:

In this circuit configuration the modern TIP packages need a 100nF capacitor soldered between the Emitter (output) and ground. This quenches a high-frequency oscillation that can occur after the replacement. I also replaced IC4, the solenoid transistor, with a TIP107 Darlington:

The oil infusion of the motor bearings had come to an end and I extracted them from the vacuum chamber:

I reassembled the motor and implanted it along with the PCBs and RPM panel in my bench unit. Then it was time for a RPM stability test with these components. This shows the BeoloverRPM device in action:

In its 'slow' mode it outputs the RPM in 10s intervals. Using a terminal program on a PC or Mac the RPM can be logged for extended periods of time for generation of a RPM stability plot. This shows the 24 hrs RPM stability graph I measured for this motor:

It is slightly choppy. This is a result of this motor having been opened before without noting the original orientation of the top bearing. If the bearing is not installed in the same orientation there may be a period where the shaft polishes a new segment of the bearing as it is pulled towards the platter by the belt. In my experience these small variations slowly go away after playing the deck for a while. At any rate these fluctuations are much smaller (~0.3%) than what humans can typically discern when listening to music (>0.7%). So this motor is ready for duty again!

I also measured 'wow and flutter' (the short term RPM fluctuations introduced by the feedback speed control system) using the 'fast' mode of the BeoloverRPM device. In the fast mode it logs the RPM after every passing of a platter rib. This reveals a pattern that repeats every 24 measurements, i.e. after each turn of the platter. It is a result of minute spacing variations between the ribs due to manufacturing tolerances. The wow and flutter RPM changes are superimposed to this pattern as a sine-wave like feature, which is normal for analog feedback-based control systems:

Evaluation of this pattern yields a wow and flutter number that is smaller than 0.1%. This is slightly larger than what the manual specifies (<0.05%), but this may well be a result of the different way they measured wow and flutter in the 1970s, where they used a test record and an analog filter based 'frequency analyzer'. The joys of analog audio!...;-).

In summary, this was a successful restoration project and these components are ready for duty again!

Beogram 4002: Failed Restoration of DC Platter Motor and Substitution with Beolover SyncDrive

I recently received the DC motor and the RPM panel of a Beogram 4002 for restoration. The unit displayed the usual RPM variations associated with dry running motor bearings.

In the end I was not able to restore this DC platter motor with a satisfying result. The reason may be that the motor seemed to have been opened before. The pulley was loose and the screws only lightly tightened. As shown below the motor still has RPM jumps around 1%, even after oil infusing the bearings and replacing the spark snubbers. My hypothesis is that the reason when I get such jumps is an mis-orientation of the top bearing after the oil infusion. When I open a motor I usually mark the bearing position and then put it back in exact the same orientation. This seems to increase the chances for a successful result.

My theory for the occurrence of the observed RPM variations is that over time the bearing gets polished in a spot facing the center of the platter due to the pull of the platter belt. If the bearing is re-installed in a different orientation the polishing process needs to start anew and this causes the speed variations. So when motors come in that were worked on previously it is possible that the bearing is already not in the original position anymore when I extract it. But I guess we will never know exactly with this motor.

Luckily, there is the Beolover SyncDrive DC motor replacement. It upgrades any DC motor Beogram to AC motor RPM stability with a simple plug-and-play installation (no soldering required):

I usually offer the SyncDrive at a discount whenever I am not able to restore a DC platter motor.

This summarizes the work I performed for this project: 

The motor as received:

I took it apart to remove the bearings:

The bearings are the two small donuts on the black pad upfront. I inserted the bearings into synthetic oil and pulled a vacuum. These bearings were very thirsty and the air bubbles drawn from them by the vacuum were so many that they caused the oil to foam before I could take a nice picture of the process starting:

After a couple days the bubbling stopped and I extracted the re-filled bearings from the vacuum:

Then I reassembled the motor and hooked it up to my bench supply. I measured a fluctuating current around 0.7-0.9 Amps at a voltage of about 1.4 V:

Way too high current at such a low voltage! The motor itself made strange pulsating noises and did anything but run smoothly. Sounded a bit like a one-cylinder farm tractor from 1938....;-). This was a clear indication of one or more spark snubbers having gone bad. They seem to occasionally short-circuit and with that one of the coils on the rotor is dead making a short circuit. Hence the high current and erratic behavior.

I set up to replace the spark snubbers with modern uni-directional TVS diodes. This shows the original spark snubbers still in place. They are the three silvery devices soldered to the poles of the rotor:

Next to the rotor on the black pad are the TVS diodes prepared for soldering in. I removed the spark snubbers:

And then soldered the TVS devices in-between the poles:

If you try this at home, the TVS packages cannot protrude into the plane occupied by the commuter terminals. Otherwise they can interfere with the brushes and/or the iron pieces of the rotor. Then I put the motor back together and tested it again:

Now I got the proper 0.2-0.3 Amps at 5 V. So I implanted the motor in one of my 4002s and measured the RPM stability over 24 hrs. This shows the BeoloverRPM in action:

In its slow mode it logs the RPM in 10s intervals, perfect for detecting RPM inconsistencies. The blue curve is the graph I measured after 24 hrs:

Sadly, the motor did not run stable enough to declare victory. The blue curve shows RPM jumps of the order of 1%, about 20x larger than what is tolerable according to specifications (<0.05%). These fluctuations may still be too small to be detected by the average human, but when listening to piano music or similar it may well be noticeable. 

So my customer decided to let me replace the motor with a Beolover SyncDrive. I added a typical SyncDrive RPM graph measured on the same Beogram (red) for comparison. This curve is as good as the curves I usually measure on AC platter motor Beogram 4002 and 4000. This will fix my customers RPM issues!

On to the RPM panel. This shows it as received:

And flipped around, revealing the bulb covers:

I removed the covers:

And replaced the bulbs with Beolover RPM Panel LED Backlights for Beogram 4002 and 4004 (Types 551x/552x). They solder directly to the solder pads used for the bulbs, i.e. are drop in replacements:

The LED boards do not interfere with the bulb covers, which can be installed the same way as before:

Then I tested the RPM panel in my 4002:

The scales are backlit in a nice warm sheen, exactly like an old fashioned incandescent bulb would do it!

All good again with this RPM panel!

New Replacement Keypad Plates for Beogram 4002 and 4004 are in the House!!

A happy day in Beolover world!!:

After about three years of time consuming and costly effort one of us (Beomazed) finally figured out how to manufacture faithful reproductions of the often worn keypads of Beogram 4002/4004/6000.

Finally, another milestone on the way to perfect cosmetic restorations achieved!...;-).

Here a couple impressions of one of the new keypads recently installed in a Beogram 6000:

The challenges were twofold:

1) First, a manufacturer had to be found who could make faithful reproductions of the original metal plates. A number of materials and processes were tried out until finally a perfect keypad plate emerged that had the proper springy feel and the perfect brushed look.

2) Then a coating material had to be found that would give the new metal plates the characteristic look of the original ones. This was pretty difficult due to the color and hue changes the original pads exhibit when observed under different viewing angles and in changing lighting situations. After many trials finally a coating was found that matched the original behavior well. While looking great, it is also an advanced material that is very durable.

It is pretty difficult to take pictures of finished metal surfaces that faithfully show the actual look observed directly.

Therefore, I removed the slightly worn keypad of my bench 4002 for taking some pictures in direct comparison under different light and camera angles. This direct comparison allows a better impression how close the new pads are to the original look.

These pictures were taken in diffused natural light:

And this one with a more harsh LED light coming in from the back on my work bench:

I think it is obvious that the new pads match the originals quite well.

Of course there are small differences as should be expected with any reproduction process. Also keep in mind that the original keypads probably looked slightly different when they were new. Most materials slowly change their optical properties as they age due to chemical and surface structure changes.

Stay tuned for updates. We will soon offer a restoration service for worn keypads.

Beogram 4000: Full Functional Restoration and a Test Spin with the Ramsey Lewis Trio

This post summarizes my work on a Beogram 4000 that I received from a customer in Australia for a full restoration. An earlier post discusses the condition of the unit as received.

This shows the unit on my bench in 'service position' after removing platter and aluminum panels:

As usual I first focused on rebuilding the carriage:

I removed all the moving parts of the tonearm lowering mechanism

and liberated the carriage from its rods and spindle:

This shows the removed components ready for the ultrasonic cleaner:

A while ago I realized that the plungers in the arm lowering solenoids often have some residual magnetization. If the magnetization gets too strong the arm will sometimes go up with a delay, which can lead to unhappy needle dragging across the record at the end of a record when the carriage returns home. So I made it a standard item of all my 400x restorations to take the solenoid assembly apart

and demagnetize the plunger. I usually test successful demagnetization with an iron setscrew:

If the setscrew cannot be pulled around with the plunger anymore the magnetization is gone.

While the carriage is up, it is the perfect moment for the removal of the solenoid activated switches and gold plating their contact terminals. This shows the three switch assemblies removed from the carriage:

As usual they were fairly oxidized and also bent out of shape from earlier attempts to fix switch malfunctions.

I usually do the gold plating of these switches together with those found on the carriage position detection board that is mounted underneath the travel of the carriage. So when the carriage is removed, it is also the perfect moment to get to the switches on this board. This shows the board still installed:

Unsoldering of the carriage motor leads and removal of two screws allows to flip this board up revealing the switch terminals and the red solenoid current limiting resistor:

I removed all the terminals from the solenoid and carriage switches for plating:

This shows them after first plating them with a coat of nickel followed by a layer of 24 carat gold/cobalt alloy (such alloys are the standard for gold coatings for electronics applications due to their higher hardness)

Beogolden!...;-). Then I soldered the terminals back into their places. This shows the three solenoid switch assemblies

and the carriage position switches:

I usually also replace the solenoid resistor with a modern higher rated power resistor. These old resistors have a habit of degrading and then getting too hot, with following failure. So it is a good idea replacing them preventatively while this board is up.

With this board out of the way it is a good moment to also replace the solenoid power transistor. Originally it is usually a TIP41A:

I this case it was reduced to being a capacitor:

This immediately explained why the solenoid would not activate when I initially tested the basic functions of this unit. I replaced it with a TIP41C, a higher voltage rated cousin of the A version:

This should help allowing this solenoid transistor to survive longer. This shows the carriage PCB installed back in its place. I also cleaned the plastic switch actuators in my ultrasonic cleaner. As so often, they were caked in old lubricants:

Then I re-installed the solenoid activated switches:

Straight and shiny! Beolovely!

While the carriage is liberated it was also a good moment to replace the MMC cartridge mount. Unfortunately, the cartridge tabs of the 4000 series were made from a plastic that has become brittle in most cases after ~50 years. So it is a good idea to replace the mount before it has a chance to break off when a cartridge is mounted or pulled off. Often the broken off tab remains lodged in the cartridge, which can be a hair-raising moment when it happens with a newly restored $800 cartridge!

It is relatively easy to get the original mount out. After removal of the tonearm, it needs to be 'cooked' for ~30 min at a low simmer:

Then the MMC mount can be pushed out with a suitable rod that fits into the aluminum profile. This shows the liberated original mount together with a new MMC Cartridge Mounting Tab for Beogram 4000, 4002, and 4004: 

I transferred the wires to the new part:

and installed it in the arm. It is a good idea to mount the part with a defunct cartridge stuck on the tab. That way the proper position of the assembly inside the aluminum tube is found easily:

After re-connecting the tonearm I replaced the incandescent bulb of the tracking sensor with a LED based assembly. This shows the original black bulb housing still in place:

Removal reveals the aperture used in the tracking mechanism to feedback-control the carriage movement:

This shows the original part together with a Beolover Tracking Sensor LED Light Source for Beogram 4000:

The small surface mount LED is in the approximate location of the bulb filament ensuring reliable functioning of the replacement part. This shows the LED assembly installed:

The small white box on top of the assembly is a potentiometer that allows adjusting the intensity of the LED. This can be helpful when adjusting the tracking feedback gain.

Then it was time to put the mechanical components back together. This shows them nice and shiny after ultrasonic cleaning:

I always replace the damper gasket with a new Beolover Damper Gasket for Beogram 4000, 4002, and 4004:

This ensures a consistent arm lowering speed. The original gaskets are often hardened and/or warped, which can result in undamped arm lowering. Another hair-riser when an expensive cartridge is on the arm!...;-). As usual for later 4000 (earlier units have an all-metal arm), the solenoid arm extension was cracked in this unit:

This extension is crucial for the functioning of the arm lowering mechanism since it activates the switch that reduces the solenoid power after full extension of the plunger. A loss of this extension would cause the solenoid to overheat and short out. Therefore, I always replace this part with a new Beolover Solenoid Arm Extension for Beogram 4000:

If you do this at home, please, make sure you fixate the part, bolt and nut in place with some epoxy. This prevents a loosening of the bolt over time as the part gets 'whacked' by the solenoid every time the arm gets lowered.

After the carriage was in place again I re-lubricated the pivot point of the damper-to-arm linkage. This linkage is mounted on the sensor arm assembly in-between the two arms. You can see it stick out towards the back of the turntable from the small V-cut on the metal plate that is bolted to the back of the counterweight assembly:

For cleaning and lubricating the pivot point the sensor arm needs to be removed. Here you can see it extracted with the linkage already removed:

Af course the small copper plate that helps lateral movement of the tonearm while it is up was loose due to degraded double sided tape. I cleaned the little plate

and reinstalled it with a dab of epoxy.

Then I installed a new Beolover Aluminum Carriage Pulley for Beogram 4000: 

The final 'act' of the carriage restoration was the replacement of the incandescent light bulb in the record detection sensor at the end of the sensor arm. This shows the small sensor compartment pulled out with the bulb still installed:

Next to it is the Beolover Sensor Arm LED Light Source for Beogram 4002, 4004 and 4000 together with its alignment aid. I installed the part:

Then it was time to restore the PCBs. First came the main PCB:

Someone already replaced the original Siemens relay:

I started with replacing the one electrolytic capacitor on the solder side:

Here a picture of the new one:

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

This shows the new Beolover Siemens Relay Replacement for Beogram 4000, 4002, and 4004 installed:

While the PCB is up, it is a great moment for also replacing the two push-pull TIP31/32 Darlington transistors that drive the AC motor. They are bolted to the enclosure bottom for enhanced heat transfer:

It immediately became clear why the AC platter motor ran intermittently when I first plugged this unit in. One of the pins was broken off inside the yellow insulation tube:

I replaced the two transistors with stronger TIP41/42 for enhanced longevity:

Then I replaced the two electrolytic capacitors on the power supply board and also the sole power transistor on this board:

Next up was were the AC platter motor and the big capacitor cans that serve as power rail reservoirs or to shift the phase of the second motor phase:

I removed everything:

This shows the extracted motor:

I took it apart

and submerged the two clamshell housing parts in synthetic oil. I pulled a vacuum to start the oil infusion of the bearings that are integrated into the clamshells. Immediately strong bubbling and foaming occurred in the oil container:

This process can take up to three days until the bearings are fully replenished. In the meantime I focused on the remaining restoration tasks. At this point most items inside the enclosure were unbolted. So it was a good moment to install new transport lock bushings. The old ones were completely degraded:

This shows the Beogram ready for vacuuming out the enclosure:

The degraded transport lock bushings had turned into a powdery mess:

It is important to remove all the small fragments since they can get lodged under the floating chassis impeding its motion. After the enclosure was clean I installed new Beolover Transport Lock Bushing Set for Beogram 4000, 4002, and 4004:

I designed them in two halves, which makes installation very simple. Just push one half in to the orifice from below

and then the other from the top:

If you try this at home, please, note that some Beograms have slightly larger orifices, which may make it advisable to add a small amount of superglue gel to hold the parts in place. This shows one of the bushings with the lock screw already in place:

Now it was time to install the Beolover Efficient 24V Power Supply and Main Capacitors for Beogram 4000 into the space previously filled with the big capacitor cans:

This part not only replaces the large capacitor cans, it also updates the main power supply of the Beogram, the 24V rail, with a modern buck converter that significantly reduces the energy consumption of the deck and with that also the fairly high heat emissions. Installation is made simple by the clearly labeled contact pads on the assembly. First I soldered the leads from the two 2200uF cans to the pads on the upper half of the board:

Next came the leads that were originally soldered to the reservoir capacitors on the other end of the board:

The oil infusion of the motor had come to completion in the meantime. I re-assembled the motor

and then soldered its four leads to the board:

At this point the board was ready to be bolted in:

The board bolts to the original mounting holes that were used for holding the original capacitors in place.

My next focus was the keypad assembly. It contains an early digital control system that manages the functions of the Beogram. After taking out the sole screw that holds it down I removed it and flipped it over. I saw that the strobe mirror had been already glued back in place. It seemed a solid connection, so I left it untouched:

I also noticed that the lower PCB had been unbolted from its hinge (which allows it to be flipped vertically for service). Luckily the hinge part and the two screws were still in place:

I reassembled the hinge and then put the keypad into service position. This shows the upper PCB that holds all the switch terminals for the keypad. As usually they were very oxidized:

The flipped up board holds most of the digital gate ICs and the light bulbs that illuminate the carriage position indicator and the two RPM trimmers. What I found explains the blueish sheen that came from the position indicator compartment when I initially tested the Beogram. Someone had installed three cold white LEDs:

I focused first on the switch terminals. I extracted them for gold plating. Very oxidized indeed!:

This is how they looked after I coated them with nickel and gold:

Much Beolovlier!...;-).

This shows them re-installed:

Then I replaced the three LEDs and the remaining original bulb with LEDs. This shows the LEDs I use for the backlighting of the RPM trimmers:

They need to be installed with current limiting resistors since they run on the 12V bulb voltage. For the position indicator backlighting I used the Beolover Scale Illumination LEDs for Beogram 4000 LED assemblies. This shows everything implanted:

and lit up:

At this point I also adjusted the bias for the sensor arm transistor to yield a DC voltage of ~1.8V at its collector:

After this adjustment I moved the bias trimmer to the component side.

Then I reinstalled the plinth after bending its mounting tabs back into proper shape. As usual the plinth washers were mostly cracked 

and I replaced them with the Beolover Plinth Guide Washer Set for Beogram 4000, 4002, and 4004:

The black one is for the front center fixture so it cannot be seen when the aluminum panels are installed. This shows one of them installed:

The next step was doing all the mechanical adjustments:

First I aligned the arms to be parallel and in 23mm distance from the platter. Then I aligned the floating sub chassis to make the platter flush with the aluminum surfaces. Next came centering the platter inside the opening in the large aluminum panel. This is done by carefully bending the threaded rods that control the tension in the leaf springs that float the chassis. All this can be a pretty tedious process and require a few iterations to get everything perfectly into place.

Usually, the next step after getting the platter and subchassis adjusted is setting the arm lowering limit and calibrating the tracking weight.

Unfortunately, I realized at this point that the arms after returning home when pressing OFF would not stay home but travel back towards the record for an inch or so until they would stop.

After a bit of thinking I realized that the culprit might be a 24V reed relay in permanent closed position causing the 24V rail to stay on after the carriage hits the off switch at the home position. 

A quick check with the multimeter confirmed my suspicion. The relay was closed even with the deck unplugged. So I extracted it from the coil:

This shows the original relay (top) with the new Beolover reed relay:

This shows the new one installed (top relay in the lower yellow coil):

For more details on the process, please see here.

This fixed the issue and the Beogram behaved normally again.

Now it was finally time to do the remaining adjustments. 

First I focused on the tracking weight calibration. I usually replace the flimsy locking washer on the counter weight screw

with a M3 nut and a washer:

The nut allows locking the calibration in place to survive the rigors of the shipping process.

This shows the final calibration:

I usually try to get the weight calibrated around the 1.2g setting on the small rotary dial next to the arm base. Most B&O cartridges seem to require 1.2g tracking weight. These dials are notorious for showing imprecise weight numbers. In general it is best to use a digital scale for calibrating the weight occasionally regardless the setting of the rotary dial.

Next came the adjustment of the tracking feedback gain to ensure proper tracking of the grooves during the advancement of the tonearm towards the center:

After completing the adjustments I installed a new all-metal DIN5 plug with gold plated contact pins:

Then it was time for my usual 24 hrs RPM stability test with the BeoloverRPM device:

This measurement (done in the 'slow' mode of the BeoloverRPM) yielded this 24 hrs RPM stability curve:

This curve shows the typical thermal drift that is typical for analog control systems. My workshop in Albuquerque changes temperature quite a bit during the night in winter due to the often freezing outside temperatures. The dip in the graph above corresponds with the unheated night hours in that room. Overall this curve is as good as it gets with the Beorgam 4000! 

The BeoloverRPM has a second mode, 'fast', where it puts out one RPM measurement per platter rib passing under the sensor. This allows a high resolution measurement that allows the determination of 'wow and flutter', in other words RPM changes that occur on a short timescale.

The fast mode usually results in an RPM graph that shows a repeating pattern:

This pattern repeats every 24 measurements, i.e. corresponds to the turns of the platter (the platters have 24 ribs on them. Every platter yields a different pattern suggesting that this pattern is a measurement artifact. Indeed there are small differences in the rib spacing around the platters due to manufacturing tolerances and this imprints a pattern on the RPM measurement. This graph shows the pattern for about 50 latter turns:

The slight superimposed waviness of the pattern actually corresponds to real RPM changes caused by the elastic coupling between platter and motor and fluctuations in the precision Wien oscillator itself that drives the synchronous motor. These fluctuations are well below the 0.05% RPM variations specified in the Beogram 4000 service manual. So all good in the RPM department of this Beogram!

Not all good was the record detection department. After the above test I did my usual test with an empty rotating platter to see if it would properly detect that there is no record. It did not and eagerly dropped the needle onto the platter! It turned out that the photocell in the sensor compartment at the end of the sensor arm had delaminated. I extracted the defect cell:

Sadly, this is an increasingly occurring issue, probably due to old age. For this reason I recently designed a modern replacement based on silicon photo diodes. This is a picture of the new Beolover Sensor Arm Photocell for Beogram 4000, 4002, and 4004:

It is a direct plug-and-play replacement for the original cell, i.e. there are no circuit modifications necessary to make this work. This picture shows it installed:

Please, read my dedicated post about the installation process for more details. After installation I qualified the sensor response with my oscilloscope. This shows the trace I measured above a rotating platter:

A very good signal with a 2.5V amplitude. More than what the manual specifies. A test with an empty platter confirmed that the record detection mechanism indeed was restored.

At this point I finally tried to play a record. It played, but only on one channel. Closer inspection yielded that one of the thin wires that connects the tonearm had broken off:

I was able to solder the two wire pieces together, which restored the second channel:

Please, read my dedicated post about this microsurgery for more details about the process.

Now it was finally time to install the Beolover internal RIAA pre-amplifier for Beogram 4000. It is a pretty simple installation process. It connects directly to the output terminals of the Beogram and the output cable only needs to be transferred unmodified to the equally spaced output terminals of the RIAA board. This shows it installed:

Read more about the installation process here. The board can be switched between RIAA amplified and un-amplified standard signal routing. This means after installation the deck can be directly used with any high-level input like DVD, CD, AUX or any modern boombox with a line input, while it also can still be used with a dedicated Phono input.

And then it was finally time to enjoy a first record on this beautiful fully functionally restored Beogram 4000! I chose a recent acquisition, a pretty awesome record released 1972 by the Ramsey Lewis Trio on Columbia Records (KC 31096). I bought this record as 'bycatch' when I was ordering another record on discogs and free shipping was offered by the seller for a couple more records from his store. And so I went through the collection and fund this one. I am happy I did! It has a very interesting rendition of one of my favorite tunes, People Make the World Go Round on side one.

Of course this record was cleaned on a CleanerVinyl ProXL setup to restore its original glory.

Here an impression of this lovely album playing on the Beogram:

Absolutely satisfying! I will now play this Beogram 4000 in my shop for some time while we wait for the arrival of a new CNC precision machined teak wood frame provided by Christian Hakansson's workshop. Unfortunately, the original plinth is damaged on the front left corner. Walk more carefully, people, when you carry your Beogram around!..;-). Stay tuned for an update!