Beomaster 8000 Type 1903 - Arizona Restoration Project - Finalizing The Repairs

This Beomaster 8000 project is almost ready to wrap up. 

I left off with this Beomaster functionally working.  To continue that, I did some music listening with the Beomaster 8000 connected to an FM antenna, an iPod (in Tape 1 and Tape 2 source inputs) and with the speaker 1 and 2 outputs connected to my workshop Beovox S-55 and MC-120.2 speakers.

At first I thought the sound was okay.  Thinking back, that itself was a little odd.  Usually I am more impressed during the first listen.  Something seemed off with this Beomaster 8000 sound so I connected up my audio testing equipment.

Here is my test setup.
I mainly wanted to view the frequency response of the Beomaster at various output levels.
For that, I used a QuantAsylum QA-403 Analyzer and my two, bench dummy speaker loads (8 ohms).

The frequency response testing showed that the output amplifier had quite a drop off in output between 20 Hz and 100 Hz (the low end).

Here is a QA-403 frequency response test output with the Beomaster 8000 at its maximum rated output, 100 Watts into 8 ohms. 

A Beomaster 8000 should output its audio signals between 20 Hz to 20,000 Hz with only a ± 0.5 dB difference.

As you can see, at 20 Hz, the output levels are around -4 dB down from where the output is at 1000 Hz!

Looking at the left and right channel Output Amplifier modules (Module 5) I spotted a problem.
These Output Amplifier modules had already been re-capped previously by an electronics shop somewhere.  They did pretty good work but on the 100uF, 16V electrolytic capacitors (there are two per Output Amplifier PCB), the technician transposed the numbers for the capacitor.  Instead of grabbing 100uF, 16V capacitors, he (or she) selected 10uF, 160V capacitors.

One of those capacitors is for the Beomaster 8000 Output Amplifier feedback.  
The gain on the feedback is especially sensitive to the value of that capacitor and the 10uF capacitor results in the impedance of the capacitor at 20 Hz to be around 795 ohms instead of 79 ohms of a 100uF capacitor.
That really knocked down the gain of the amplifier output at the lower frequencies.

Here is a photo of the Output Amplifier boards as they were with the incorrect capacitor values.

The accidental selecting of the wrong capacitor values there didn't cause any catastrophic problem to the Beomaster but it did rob the Beomaster of its low frequency performance.  That is the problem I was hearing during my first listening tests.

Here are the boards now with the correct capacitor values installed.

Remeasuring the Beomaster 8000 frequency response at 100 Watts output across the 8 ohm dummy loads show a much improved low end.

The low frequency output is now very close to the -0.5 dB limit specified in the service manual.

The high frequency output is a little off from 0.5 dB at 20,000 Hz but for now, that isn't something I am going to address.

Listening to music on this Beomaster 8000 is now noticeably improved over what I was hearing before.

That problem and fix was an unexpected detour task on this Beomaster.  I had planned to fix the FM display segment problem and the broken lid lever problem discovered earlier in the initial assessment of the project.

Here is the broken lid lever problem.
 

The plastic lever had broken in half but the lid damper also had a couple of problems.
Highlighted in red, above...A plastic hook on the lid damper frame was also broken.
Plus, the damper was leaking damping grease.

One thing to note though, the damper and lever are for slowing down the opening of the lid, not the closing.

The Beomaster 8000 lid is sprung so that it pops open and remains open until someone manually closes it.

It turned out, this Beomaster 8000 lid had another problem besides the damper and damper lever.
The lid assembly itself, had a broken cover for the spring that raises the lid.

Here is a photo of the broken lid and the replacement (spare) lid that I have to replace it with.

I think that I can (later) design a fix for the broken lid assembly but for this project, this Beomaster gets a replacement lid.

For the lid damper fix I also provided a replacement damper from my collection of spare parts and a new, replacement lever that I got from DKSoundParts.

For the lid damper damping grease, I tried two different types.  I have used these two types before.
The Nye Lubricants PG-44A is the thickest damping grease I have come across.  Its high viscosity is really good on Beogram 800x turntable lids.  The Rocol Kilopoise is supposed to be what B&O originally used on these dampers.  Its viscosity feels about half the viscosity as the PG-44A.

However, I ended up going with the Kilopoise filled damper on this Beomaster.  I felt the higher viscosity PG-44A put too much pressure on the plastic lid lever and I didn't want it to break again.

Next was the FM display segment problem.

In my earlier testing of the Beomaster 8000 I noted that one LED segment and the LED period were not illuminating on the FM display.  I have highlighted those in the picture below.

On this project, the plan was to only fix the broken display segments, not go to the expense of replacing the whole set.

That being the case, I took a fully functioning FM display module from one of my spare Display boards.

I tested the faulty FM display and the replacement FM display on a test fixture I designed for these B&O LED display modules.

With my bench power supply I was able to increase the current and voltage to get the missing LED period to illuminate on the faulty display.  That took more voltage and current than it should and the display got a little warm.  Also...There is still the same missing LED segment.

The picture below shows both the old and new displays on the test fixture.

Here is the Beomaster 8000 with the replaced FM display module installed on the Display Board.
I tested it out as I also tested listening to the Beomaster FM tuner.  Both worked perfectly.

Now to carefully reassembly the Beomaster 8000 and do some more functional testing before returning it to its owner.  

I still need to connect up actual Beosystem 8000 components to verify that the remote control functions all work.  

Beomaster 8000 Type 1903 - Arizona Restoration Project - Replaced Microcomputer Board Testing

I decided to go with my already restored, early serial number Beomaster 8000 09 Microcomputer module in this Beomaster 8000 receiver.  I re-installed the original unit's metal shielding box on the replacement 09 PCB.

After working with this early serial number Microcomputer PCB, although the shielding box is a pain to work with, I should have removed it by focusing my de-soldering work on just the tabs that were soldering onto the shield box lids.

Reinstalling the box is much easier than removing it.

Here is a picture of the new Microcomputer PCB at the corner where the original board had broken traces.
Everything is good with this 09 module.

Here is the new Microcomputer board reinstalled in the Beomaster 8000 cabinet.

I went through all of the control panel functions both with the control panel buttons and the remote control buttons.

Everything worked as it should except that the FM station display has the two missing LEDs.

I can deal with the display LEDs later.

Right now I wanted to try out this Beomaster 8000 and see how it sounds.

Before doing that though, I needed to check the No-Load Current and DC Offset of the Beomaster 8000 Output Amplifier boards per the service manual.

Both the No-Load Current and DC Offset values needed adjusting.  

Here is the No-Load Current check after I adjusted the TR226 trimmer on both channels.

Note: These checks and adjustments are made with no speakers connected and the volume at zero.

No-Load Current

DC Offset

Those service manual adjustments encountered no problems so I moved on to some real listening tests.

I connected up an FM antenna and an iPod Nano to Tape 1.
I connected a pair of Beovox MC 120.2 speakers to Speaker 1 outputs of the Beomaster.

I will leave the Beomaster 8000 playing for several hours with the volume level at a low volume level (2.4).

Beomaster 8000 Type 1903 - Arizona Restoration Project - Microcomputer Board

Having determined the Microcomputer PCB (Module 09) has a problem in this Beomaster 8000 receiver, I removed it to examine it more closely.

I am not fond of these Microcomputer (uC) PCB modules from the early serial number Beomaster 8000 units.

B&O decided to solder the top and bottom (metal) lids of the uC assembly to the PCB. On later serial numbers, B&O changed the PCB shielding to be a metal frame around the PCB with snap-on lids.

To remove the metal lids on this uC PCB, the board connections have to be de-soldered.
It is safest here to use solder wick on the six mounting spots.

Here is the 09 PCB with the metal lids removed.

Right away I could see some breaks in the 09 PCB traces near connectors P75 and P76.

I verified the open trace connections with my DMM then set about repairing them.
Of course I hoped this would be the single source of the 09 Module problems and could move forward.

Here is the PCB 09 with the breaks in the traces bridged.  On the wider traces I decided to use some copper strips.  On the two thin traces I just used some signal wire.

Note that while I had the 09 PCB on the soldering station, I reflowed the solder joints on all of the 09 PCB connectors.

I tested the connections again with my DMM, then re-installed the 09 PCB in the Beomaster to try powering it on again.

This time I do get the Standby LED with this original 09 PCB.

The control panel buttons do not consistently operate the Beomaster 8000 though.
I double-checked source selection, volume control and FM tuning using a Beomaster 8000 remote control.

That worked so there is an issue with the control panel buttons connected to this original 09 PCB.

With the remote control though, I checked out some of the Beomaster 8000 functions.

I could select all of the sources but the FM tuning did not work.  The lack of FM tuning was a reason the owner sent me the Beomaster 8000 so at least the reason for that problem makes sense.

This picture shows the selection of FM presets P1 and P8.  You can see that the FM tuning indicator is not correct.  The tuning control couldn't do anything that made sense on the display either.

This photo shows source selections for phono and tape 1.  I also checked tape 2.  Those all select fine except that I had to do the selections from the remote control.

My next test was to uninstall this original 09 PCB and replace it with one of my Workshop Beomaster 8000 09 PCB modules again.  This time, however, I grabbed my Workshop 09 PCB from an early serial number Beomaster 8000.  That is a better match than the late serial number 09 PCB I tested with earlier.

Here is my Workshop 09 PCB next to the fault 09 PCB from this Beomaster unit.

They look identical except that my Workshop 09 PCB has a new 22uF capacitor and 1uF capacitor.
It also has new oscillators.

With my Workshop 09 PCB installed, the Beomaster 8000 source selections, volume adjustment, balance adjustment and FM tuning all work.  Both from the control panel and the remote control.

I can see that a separate issue with this Beomaster 8000 is on the display segments. 
The FM tuning display is missing one segment and the period for the frequency display.

What I have to do next is figure out what the solution will be for this Beomaster 8000 unit.

This project has budget and time constraints that limit my choices.

That leads me to wanting to just replace the original 09 PCB with my, already restored and working, Workshop 09 PCB.

The time it would take to troubleshoot and rework the broken 09 PCB could be expensive and at the end, it would still be a PCB that had repairs to some broken traces.  I could live with that if this were my own Beomaster 8000 but not when it is a unit that has to be shipped back to an owner.

Another option would be to assemble a new 09 PCB from scratch using a new PCB from Fredrick Adenholm.  He has reproduced the Beomaster 8000 Output Amplifier PCB, Display PCB and uC PCB.

I have all three of those blank, ready to populate boards.  The 09 PCB is pictured above.

However, in the case of this project, doing that to replace the 09 PCB is out of scope.

Beogram 4002: Restoration of DC Platter Motor

I recently received a Beogram 4002 DC platter motor from a customer in France for restoration. His Beogram had the usual randomly occurring RPM variations. Something that will most likely be fixed by re-infusing the dry motor shaft bearings with oil under vacuum. Most of these motors have bearings that lost all of their stored oil, and this causes the shaft friction to increase significantly.

This shows the motor as received:

I disassembled it to extract the shaft bearings:

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

The bubbling indicates that air is being drawn from the pores of the Oilite-bearing material. The leaving air is successively supplanted by oil in a diffusion process. The process has completed when the bubbling stops. In this case, this happened after about two days. At that point, I extracted the bearings from the vacuum chamber:

Then I reassembled the motor with a new Beolover DC Platter Motor Pulley for Beogram 4002 and 4004 and installed it in my bench Beogram 4002 for testing with the BeoloverRPM device:

The BeoloverRPM is able to log the RPM in 10s intervals into a serial port of a computer over long periods of time. This allows precise detection of intermittent RPM deviations that otherwise would be difficult to detect. This is the graph I measured after about 24 hrs:

This flat curve is 'as good as it gets' with Beogram DC platter motors! This motor is ready for duty again! It is time to send this motor home to France for another tour of duty in its Beogram 4002!

 

Beogram 4002 (5523): Full Functional and Cosmetic Restoration, and Installation of Upgrades (SyncDrive, Commander Remote and Carriage Motor)

This post discusses the restoration of a Beogram 4002 (Type 5523 with DC platter motor) that I received from a customer in Louisiana. He commissioned a full restoration and upgrade with the Beolover SyncDrive, Commander remote control, and a new Beolover carriage motor for quieter operation.

This shows the final result of my efforts:

The following gives a detailed description of what it took to get there!

This shows the unit as received on my bench with the aluminum panels and platter removed:

I started out with the DC platter motor. They usually need their shaft bearings infused with fresh oil under vacuum. This shows the motor as extracted from the enclosure:

The pulley on this motor was non-spec. It was also lacking a crown, i.e. the run surface was a cylinder instead of having a bulge that keeps the belt centered. Sadly, many replacement pulley offerings on ebay etc... have this defect. This motor received a properly designed Beolover DC Platter Motor Pulley for Beogram 4002 and 4004 after the oil infusion had been completed. This shows the disassembled motor:

I put the bearings (the two small donuts on the black pad upfront in the above picture) into synthetic oil and pulled a vacuum. Immediately, strong bubbling started:

After a minute, the oil had foamed up considerably:

This suggests the bearings were pretty 'thirsty', which matches the screeching sounds the motor made when I briefly tested the unit initially. The infusion process is terminated when the bubbling stops. This usually happens after 2-3 days. So, in the meantime, I focused on the remaining restoration tasks.

First, I worked on restoring the arm lowering and carriage translation mechanisms. This shows the original condition:

I removed all the components for ultrasonic cleaning and re-lubricating:

This shows the liberated carriage:

I usually put it on a soft pad to protect the fragile wiring on the underside. I also removed the solenoid

They often have magnetized plungers from years of actuating the arm-lowering mechanism. I removed the plunger for demagnetization:

This one showed evidence of magnetization: It was able to attract a ferrous setscrew:

I worked on it with my tape head demagnetizer until it did not attract the screw anymore at close distance:

This is an important step of any Beogram restoration. A magnetized plunger is often the root cause of delayed arm lifting during the auto return at the end of a record. Not a happy moment when the new $800 cartridge from tonabnehmerservice.de drags across the record for a few inches until it finally gets lifted up!

While the parts were in the ultrasonic cleaner, I started working on the restoration of the PCBs. The main PCB has two power Darlingtons installed on the solder side. This shows 1IC1, which regulates the 21V power rail. It is usually a TIP120:

I replaced it with a TIP102, its stronger cousin:

I also installed a 100nF capacitor (yellow) between its emitter and a conveniently located GND pad. This capacitor is necessary to quench high-frequency oscillations that can occur with modern TIP transistors in this circuit configuration. The original ones do not seem to have this issue. After replacing the other solder-side-mounted 1IC4 with a TIP107, I removed the board to work on its component side. This shows the board as received:

It already had its capacitors and trimmers replaced.

Here is a detail shot of the RPM section consisting of a new relay looking suspiciously similar (I guess, being copied is the highest form of flattery...;-) to a Beolover Siemens Relay Replacement for Beogram 4000, 4002, and 4004, and the two trimmers to its left were replaced with new single-turn types:

I could not help noticing that there were some incorrect capacitor values installed:

C10 (here 2.2uF) is usually a 0.47uF or 0.33uF value.

I decided to bring all this up to 'Beolover standard,' and I replaced all electrolytic capacitors, power transistors, and the record sensor transistor with new parts. The single-turn RPM trimmers were replaced with modern 25-turn encapsulated trimmers for better adjustment accuracy. I left the relay in place since the copycat also used the exact same relay I am using on his board. So no reason to exchange it. This shows the rebuilt board:

Here is a detail shot of the rebuilt RPM section:

Next, I removed the keypad cluster and extracted the output PCB, which is located beneath the keypad.

This board features the output relay and its delay circuit:

I replaced the relay and its electrolytic capacitor, and I also installed a (red) switch that allows connecting signal and system grounds in case there is a hum in the audio signal when connecting the Beogram to an amplifier:

With the keypad out, it was a good moment to replace the incandescent bulbs in the RPM trimmer panel above the keypad. This shows the extracted panel flipped over:

Removing the covers revealed that a set of Beolover RPM Panel LED Backlights for Beogram 4002 and 4004 (Types 551x/552x) already had been installed:

The installation was less than perfect:

So I removed them and cleaned everything up for reinstallation:

For the best visual effect, these little boards should be installed flat on the original PCB and also fully centered.

I replaced the bulb covers:

It was time to reassemble the carriage. This shows the shiny,

cleaned mechanical parts back from the ultrasonic cleaner:

I always install a new damper gasket:

Replacing this gasket is an important item since the arm lowering speed depends on it. The original gaskets are usually hardened and/or deformed, and that can cause episodes of undamped arm lowering. Not a happy moment when that newly rebuilt cartridge crashes on the platter!

I installed all the other components. My customer opted for upgrading the carriage motor with a new Beolover Carriage Motor for Beogram 4000, 4002, and 4004. This shows the original motor still in place:

I unsoldered the leads and took it out. This shows the opened enclosure:

And with the new motor inserted:

It is vibration-insulated by two EPDM rubber rings that also increase the motor's diameter to match the enclosure.

This shows the new motor installed together with a new Beolover Aluminum Carriage Pulley for Beogram 4002 and 4004 and a new belt"

This unit already had a Tracking Sensor LED Light Source (Beogram 4002 and 4004) installed:

Unfortunately, the plastic housing was damaged by overtightening the screws. So I removed it, which revealed the tracking aperture:

and replaced the plastic part with a nice new one:

Next, I replaced the light bulb in the sensor arm with a Beolover Sensor Arm LED Light Source (Beogram 4002, 4004 and 4000). This shows the small compartment at the end of the sensor arm pulled out with the bulb still installed:

Next to the bulb compartment is the small LED board together with its alignment aid.

This shows it installed:

The final task on the arm lowering system was cleaning and re-lubricating the pivot point of the damper-to-arm linkage. It is located between the tone- and sensor arms. You can see it stick out from the V-cut in the small plate that is bolted to the counterweight in the picture below:

I removed the two screws that hold the sensor arm down. Then I removed the linkage:

After cleaning and lubricating the linkage, I put everything back together and then reattached the little copper plate that helps the arm move laterally when it is in its up position:

The final step was adjusting the arm alignment to get everything perpendicular to the rods the carriage travels on. I now always use my very convenient recently developed Beolover Arm Alignment Tool for Beogram 4000, 4002 and 4004:

It makes it a snap to align the sensor arm base with the rods and then the sensor arm. Once that is in place, the tonearm can be parallelized using a caliper.

This concluded my work on the carriage. It was time to empty the enclosure and vacuum

out the remaining transport lock bushing fragments. They need to be removed since they can impede the free movement of the floating chassis. This shows the cleaned-out enclosure:

Then it was time to install a set of new Beolover Transport Lock Bushing Set for Beogram 4000, 4002, and 4004 on the floating chassis. The three bushings come in two halves each. This makes installation very easy. Simply insert one of the halves from below 

and the other from the top:

Note that some Beograms have slightly larger orifices for the bushings. It is generally a good idea to use a bead of superglue gel on the vertical parts of the bushing halves to lock them in place.

This shows one of the transport locks partially re-assembled around the new bushing:

After completing the transport locks, I installed a Beolover Main Reservoir Capacitor for Beogram 4002 and 4004 (Types 551x/552x). This shows the original single capacitance setup:

Since this Beogram came with a standard reservoir capacitor, i.e., the installation of the new Beolover assembly was easy. All I had to do was solder the white and black wires to the respectively labeled solder pads on the capacitor board:

My next task was replacing the very grimy power cord:

After the cord enters the enclosure, it connects to the fuse box. This shows the box opened up: 

It is good to leave the fuses in place when soldering connections in the fuse box. The heat can loosen the attachment of the terminals to the plastic, and the fuses help keep things straight until the plastic hardens again. I unsoldered the power cable:

Then I removed the screws that hold the fuse box to the enclosure bottom and flipped the box around. After removing the cover, the wiring can be seen:

Before the old cable can be removed, the cable gland that secures the cable against getting pulled out needs to be extracted from the feedthrough orifice. This can be done with suitable pliers. Pressing the locking piece further into the cable allows pulling the gland out:

Then the gland can be removed from the cable:

Installation of the new cable is in reverse: After feeding it through the enclosure orifice, it can be pushed into the fuse box and soldered to the terminals:

This shows the fuse box bolted back in and the cable routed to the orifice:

For installing the gland on the new cable, a 'bigger gun' is necessary since the cable needs to be deformed so that the gland can reach its design diameter:

Once the gland has been pressed together suitably, it can be installed in the orifice:

Beolovely! On to replacing the equally grimy RCA output cable: 

Luckily, I had an original B&O fully shielded RCA cable from a recent partout of a hopelessly damaged Beogram 4004:

These original cables are of great quality compared to most things they sell these days: Multistranded signal wire and a fully braided signal return in each separately insulated wire. Nowadays, you can count yourself lucky if there is an aluminum foil shield. Two RCA jumper cables that I initially bought on Amazon for this project, with the plan to cut the plugs on one side for installation, had no shielding at all. They looked good from the outside, but on the inside, there were just two individually insulated straight wires for signal and return. I guess this can work as long as the cable is short enough and the external stray fields from the environment are not very strong. In such cases, the EMI cancels out on both of the wires due to their close proximity and the opposing direction of the current.

Anyway, my first step was cutting off the corroded original plugs for replacement:

For the record: the yellow wire/gray plug is the left channel if the cable is connected in the factory way on the other end.

I installed two nice new all-metal RCA plugs with gold-plated terminals:

This shows how I implemented it on the other end:

In the meantime, the oil infusion of the bearings had concluded. I extracted the bearings from the oil vat in the vacuum chamber:

Then I re-assembled the motor and installed a new Beolover DC Platter Motor Pulley for Beogram 4002 and 4004:

Note the bulge in the center of the run surface. This is called a crown and serves the purpose of keeping the belt centered when the pulley turns. If the shape is a flat cylinder, the belt will scrape either on top or on the bottom and make noises. This, of course, also affects wow and flutter. I installed the motor in the Beogram and ran a 24 hrs RPM stability measurement with my BeoloverRPM device:

The BeoloverRPM has two operational modes. In 'slow' mode (shown above), it measures the RPM in 10-second intervals and sends the data to a serial port of a computer, where it can be recorded with any generic terminal software. This allows plotting the RPM over long periods of time using Excel or similar software. This shows the result of my 24 hrs measurement:

This is quite a nice result for any Beogram DC platter motor! As good as it gets! Next, I collected some high-resolution data in the 'fast' mode of the BeoloverRPM:

In this mode, the device sends an RPM measurement every time a platter rib passes underneath the sensor. This results in 24 RPM measurements per platter turn (there are 24 ribs). This allows visualizing short-term RPM changes caused by the feedback-based motor control circuitry. This graph contains the data covering ~35 platter turns (~70 sec):

The prominent 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 for every platter turn (sort of a 'platter fingerprint'), 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% value 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. I see it for all Beogram motors that I restore. Back then, the measurement was carried out with a test tone on a test record. In these measurements, deviations from the tone 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 in the first place since humans typically start recognizing frequency fluctuations above the 0.7% threshold, i.e., the RPM fluctuations of this Beogram are well below this value, whether the number is 0.05% or 0.1%. This motor is definitely ready for duty again!

After this successful test of the motor, I did the electrical adjustments: First,

I adjusted the bias of the sensor arm transistor to yield 4V on the collector:

Then I moved the adjusted trimmer below deck to the component side:

Then it was time to measure the sensor response:

The above oscilloscope trace was measured on the collector of the sensor arm transistor while I spun the platter manually with my finger. Each dip corresponds to a black platter rib passing underneath the sensor. The measured amplitude is 7V, which is a very solid result. This record detection sensor is in great shape again!

This Beogram was nearing completion, and it was the moment for doing all the mechanical adjustments to align the platter and arms and get the floating chassis situated properly. But before I was able to do that, I still needed to install the new wood plinth and keypad so I could seat the aluminum plates properly, a prerequisite for doing the adjustments.

First, I worked on the wood plinth: I removed the metal pieces from the original wood frame by baking the frame for an hour at 250F in my oven. This softens the old adhesives, and one can cut the pieces from the wood with a carpet knife. This was followed by soaking the parts in isopropyl alcohol overnight and then rubbing off the old glue. After the metal pieces were clean, I applied 3M adhesive to them:

Then it was time to attach the metal pieces to the new 4000c style oak frame. I use two of the small aluminum plates for aligning the metal piecers with the frame. The aluminum plates have exactly the thickness needed for this process:

The challenge is to get the metal pieces all the way into the corners while they are sticky. My solution is to use strips of parchment paper to keep one side from sticking while the other is pushed all the way into the corner and pressed to the wood. Once this bond has been made, the parchment paper can be removed, and the other leg of the piece can be pressed into place using the aluminum surface as a guide.

The other side is done the same way:

This shows the completed transfer to the new oak frame:

Then it was time to replace the worn keypad with a newly restored one (see here if you are interested in getting your keypad fixed). This shows the original keypad and restored replacement in direct comparison:

It is obvious that the original keypad is way too shiny, indicating that the coating had been removed.

The original keypad had cracked RPM panel alignment pieces. Luckily, there are exact reproductions available at the dksoundparts store in Denmark. This shows old and new in direct comparison:

The new pieces do not come with the metal springs installed, so one has to transfer the original springs:

It is an easy process to put them in place:

This shows the new pieces installed on the new keypad assembly:

When I was about to stick the keypad PCB into the new assembly, I realized that the plastic plunger assemblies were all caked up with old lubricants. So I removed them and put them in the ultrasonic cleaner for a few minutes. This shows the cleaned parts:

I plugged them back into the PCB:

This shows everything back together:

With the keypad out, it was the perfect moment to install the first upgrade, the Beolover Commander Remote Control for Beogram 4002 and 4004. The module plugs directly into the keypad header on the main PCB:

Once the Commander board is installed, the keypad cluster can be seated:

The LED auto-repeat indicator of the Commander system bolts in under the mounting screw of the keypad.

It is a good idea to hold the RPM panel wiring in place with a strip of adhesive tape:

This prevents interference with the harness connecting the small LED panel and the RPM panel can be seated properly:

With frame and keypad in place, I started 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 square M3 nut:

This allows locking my tracking weight calibration in place so it can survive the shipping process. Before I did the weight calibration, I adjusted the arm lowering limit:

The tip should stop about 1 mm above the lower parts of the platter ribs as shown above. Then I used a digital weight gauge to adjust the arm counterweight to get 1.2g weight at the 1.2g mark of the adjustment wheel:

The adjustment wheel is not very precise, and it is a good idea to check the tracking weight occasionally with a gauge to make sure the weight is still correct.

Then I adjusted the tracking feedback:

My customer decided to replace the original platter motor with the SyncDrive. The SyncDrive puts DC motor Beograms on par with the older AC motor models in terms of RPM stability and wow and flutter, while giving them the absolute RPM accuracy of the later 8000/8002 models. This shows the SyncDrive installed:

Time to give this restored Beogram a first spin! I selected one of my favorite CTI albums: Stanley Turrentine's "Cherry", which he released in 1972 together with Milt Jackson (CTI 6017). I love the cover art of CTI albums! This shows this lovely album playing on this perfectly restored Beogram 4002:

The Beogram played perfectly!

It was time to install the new hood and aluminum trim to complete this project! I used a razor blade for prying off the side parts of the aluminum trim. This revealed the mounting screws:

This shows the new Dust Cover for Beogram 4002, 4004 and 6000 and reproduction aluminum trim together with the liberated metal hinge part:

A while ago, I cracked a hood due to interference between plexiglass and metal hinge. For this reason, I always test new hoods if they scrape on the metal or not before I install them. This hood passed with a minimum gap of about 1 mm:

There is a little flaw in the design of these new hoods: They have a recess in the plexiglass just where the aluminum trim bends down on the sides. That makes it difficult to get a precise bend of the trim since there is a void right at the edge. I alleviate this issue by epoxying 3D-printed plastic bits into the upper end of the recess to fill the void.

Once the epoxy is hardened, I trim the bits with a razor blade to get them flush with the plexiglass edge.

After this design improvement, it was time to install the hood! I removed the hinge assembly and set up my alignment tools for the aluminum trim:

I used a strip of blue tape to make an alignment mark:

Then I bolted the hood in again. This time I put some white glue into the threads to prevent the bolts from coming loose. They cannot be tightened very much since it is easy to crack the plastic when the bolts are too tight:

Then I applied the aluminum trim and used my bending block for making sharp bends in the trim down the sides of the hood:

They are looking pretty good:

I mounted the new hood to the Beogram.

Soon it will be time to send it home to its owner in Louisiana!

I carried it to my photo studio and took a few nice pictures. Enjoy!: