Beogram 4000: Installation of a New Precision Machined Solid Teak Frame

I recently received a lovely new CNC machined solid Teak plinth from Christian Hakansson, to be installed on the Beogram 4000 that I recently functionally restored.

Unfortunately, this Beogram had an original plinth that was damaged at the corners (please, watch out for door jambs when you carry your Beograms around!!...;-):

I removed the plinth:

If you do this at home, please, note that there is a 5th bolt under the keypad, i.e. the keypad needs to be removed before the plinth can be extracted. 

The deformed particle board under the veneer suggested that this plinth not only had damaged corners, but also had been in contact with too much moisture at some point in time:

The installation of a new plinth requires that the metal fixtures be removed from the old plinth to be transferred to the new one. I usually wrap the plinth in aluminum foil and then I put it into the oven for an hour at 200-250F. Once it comes out the metal parts can be separated with a suitable spatula or similar:

Once the parts are off, the residual contact cement

needs to be removed. I usually soak paper towel with isopropanol or goo gone and wrap the metal parts in it:

I put aluminum foil around it to prevent evaporation:

After 24 hrs the glue can be rubbed off with the drenched paper towels:

This shows one of the cleaned metal fixtures:

I use ultra thin 3M 300LSE adhesive tape for the installation. This makes the process much cleaner than with contact cement. The tape can be cut out with a razor blade to match the frame shape:

It is important to not cover the little spring tabs that are in the back of the frame:

Otherwise they can get glued to the wood and are not able to perform their duty (holding the plinth in place once it is pushed back) anymore.

Now comes the moment where the metal parts are glued to the wood. This is probably the most difficult task since one only has one try and the parts need to be placed precisely at the right level on the frame. This is greatly simplified by using the aluminum panels of the Beogram. They have the right thickness and can be used to align the metal parts with the frame.

It can be challenging to get the metal parts all the way into the corners since there is adhesive on both sides. I usually deal this issue by using some parchment or wax paper to prevent one side from sticking, while I push in the part all the way into the corner:

This shows one side glued while the other still has the paper in:

Sometimes the metal parts are not entirely conform with the frame in the corners. Many Beograms actually came with this issue 'factory installed'...;-). I sometimes use tongue-and-groove pliers to help seating the metal parts in the corners. Be careful not to damage the frame if you do this at home: 

This shows the new frame with installed metal parts:

And here a couple happy shots of the Beogram 4000 with the new frame installed. Beolovely!!:

Beogram 4000: Installation of a Brand New Beautiful Solid Oak Plinth! - Very Beolovely!!

Another Happy Day in the Beolover's life! Recently I received a shipment with two new Beogram plinths from Matt Spangler in Oregon, who is the owner of Vintage HiFi Nut. He specializes among other things in restoring/replacing wood cabinets of vintage HiFi. 

A while ago I sent him each a Beogram 4000 and a Beogram 4002 plinth. Both had been mashed up during shipping due to poor packaging. Unfortunately, this is a common issue since many people underestimate the raw forces in play during the handling of packages in sorting centers and on trucks etc...

Anyway, I received these two plinths back a few days ago. Today I had a look:

The top one is the 4002 type and the bottom one the 4000 type. Wile they look very similar, the metal frames are different in 4000s and 4002/4s due to the different size of the keypad clusters and aluminum plates. Here is a detail shot of the very well defined corners:

The top frame was made from solid Granadillo (aka 'Mexican Rosewood'), while the bottom frame was made from solid Oak. The original hardwoods that B&O used, Brazilian Rosewood and Teak are protected species these days due to over-harvesting, and so one has to use alternative hardwood types if hardwood looks are desired.

B&O did use oak in 'the day' on a smaller number of Beograms, i.e. an oak replacement can be considered 'original'. Personally, I think with wood cabinets one can have a bit of an open mind, and whatever looks great on these iconic vintage designs is great!

This is the sad look of the Beogram 4000 that I received recently:

I bought this Beogram 4000 from a seller in Germany. Unfortunately, despite pointing him to my packaging video, he did not believe in double-boxing and foam padding, and so the unit got mashed up a bit on one corner. The padding he used was less than an inch and so this was almost predictable.

While the right side only came unglued, the left was damaged beyond repair:

So when I received Matt's new frames, I decided to try out the solid oak 4000 frame on this unit. I removed the aluminum panels, platter and keypad to be able to remove the damaged plinth:

Then I installed the solid oak one that carries the 4000 metal frame. Here are a few impressions of the awesome look of this new plinth:

I absolutely love this fresh and happy oak look! A perfect complement to the bright aluminum plates. In my opinion it looks better than the original teak frame (oh, what heresy!!...;-). Matt really did a wonderful job with this cabinet! I cannot wait to install the Granadillo frame on a needy 4002.

This Beogram 4000 is on its way to a like-new look and performance! I will fully restore it and then it will be available to another B&O enthusiast! Stay tuned!

Beogram 4000: Exchanging the Plinth Panels

The Beogram 4000 that I am restoring right now came with a shaved off plinth corner (why can't people be more careful when they lug their Beograms around?? Just walk slowly and watch out for door jambs!...;-). This is how it came:

Since 4000 plinths are rare like the 4000 itself, most likely you will need to get the plinth wood panels from a 4002 or 4004. This means the metal fixtures on the plinth need to be exchanged, since they are slightly different due to the different keypad shapes (see here for more detail on the differences).

The first step is to remove the plinth, which is held by 5 screws to the metal enclosure. One of the screws is under the keypad, i.e. it needs to be taken out if you do this as a separate procedure.

Once the plinth is out the metal fixtures need to be removed. This is best done by 'baking' the plinth for ~30-45 min in an oven set to the 'warm' position, which usually yields about 80C. I usually wrap the plinth in aluminum foil to ensure a more homogeneous temperature distribution.

After the plinth was heated up, I took it out and removed the metal parts by jamming a spatula in-between. The heated old contact cement gives way fairy easily:

Take care to not damage the veneer while doing this.

The next step is the removal of the old glue from the fixtures

which is easily done by wrapping them into isopropyl alcohol drenched paper towel

followed by aluminum foil to prevent evaporation:

After letting the parts 'stew' for an hour, the glue can be wiped off with the drenched paper towel:

The glue on the wood panels needs to be left in place to not damage the veneer, but that is not a problem since it usually seems to be very thin and well distributed. I think the wood absorbed the glue when they applied it.

The next step is to assemble the panels of the replacement plinth from the 4002 or 4004, which of course also had to be liberated from its metal fixtures with the above approach.

I use Gorilla wood glue and some specially designed clamps that can hold the panels precisely in place:

After the glue fully cures (~24 hrs), the next step is to glue the metal fixtures back into the wood frame.

The first step is applying fresh contact cement to the metal parts

 and the wood panels:

I use small foam blocks for distributing the glue

Key is to make a thin homogeneous layer, and one does not have much time with modern contact cements. It is best to do it in separate steps for each side of the plinth.

After the cement is fully cured (~5 min) precise alignment is key during assembly. Otherwise the plinth will not be aligned properly with the aluminum panels of the Beogram.

Luckily one can use the Beogram aluminum panels themselves for the alignment process.

Place them on a flat surface and tape them down in an aligned way. On the outside I use a straight ruler. The aluminum panels have just the right thickness to 'lift' the metal parts to the correct position inside the wood frame:

When assembling the cement coated parts, it is crucial that they are aligned before they are pressed into place. This is difficult with a L-shape, since it needs to be pressed/moved in x- and y- direction at the same time. The trick is to insert a parchment or wax paper strip on one side of the L and then press the other into place:

Once one side is in place, slide the paper out and press the other side into the frame.

And that is the result:

One word of caution, when transferring plinths: They appear to come in two slightly different widths:

This caused an issue with this Beogram 4000, since the first time I did this process I used plinth panels that were the wider type, while the shaved off plinth was the narrower type. This caused the transferred plinth to not align properly with the enclosure, and one of the corners came unglued again due to the stress on the frame. So, the above pictures actually show the second time I did this for this Beogram. A hint if you have to remove metal fixtures that were just glued with modern contact cement: The modern stuff still gets soft when heated in the oven, but does not come off by soaking in isopropyl alcohol anymore. I think it is a different formulation for quicker drying with some probably 'happy making' organic solvents involved...;-). The trick is to replace the isopropyl with 'Goo Gone'...same drenching process with paper towel/aluminum foil.

Anyway, this Beogram 4000 plinth is fixed!

Beomaster 6000 (2702) restoration: restoring the key panel

UPDATE at the end of this post

The key panel of the Beomaster 6000 quad is an interesting design that can also be found on the Beogram 4002/4004/6000 (not on the BG4000), the Beocord 5000 (type 47XX) and even to a certain extent, on the Beomaster Commander. 

Little information is available on the construction of this key panel, so I made a small drawing of all the elements that make up this key panel.

The actual contact is made by pushing on the metal "tongues". Under these tongues is a locking plate (in black plastic) that is glued under the key panel. This locking plate then pushes the small purple plunger  against a copper plate that makes electric contact with the copper bridge in the switch. Quite a long journey to make a contact !!

The metal key panel is made of stainless steel spring steel. It is brushed on one side (the visible side) in an industrial way with stainless steel brush rollers with a grid of 400-600. I have tried to replicate this brushed aspect on another key panel that had been sanded by someone, but did not succeed. It is impossible to get perfect straight brushed lines into the metal without using the proper industrial equipment. 

The steel plate is also coated on top to give it a more satin/matt aspect in stead of the bright shiny steel. This coating is often gone on the keys that are mostly used. That creates the typical finger prints that are seen. The grease of the skin affects the coating over time.

It is also interesting to see that the steel plate tends to bend upwards if the glue is dried up  after several decades and releases the steel plate. There is reason for this! The steel plate is made out of a flat piece of metal, but is then rolled to get a certain curve (see picture). This is done to create a pre-tension on the "tongues" and to make sure that the locking plates firmly touch the underside of the aluminium frame in rest. By doing this, the tongues should be perfectly flat with the rest of the panel and it also assures that no false contact is made in the electric switches.

After this rather long explanation, let's start to take the panel apart. First thing to do is to remove the locking plates. If not, you can not remove the key panel from the frame. On this particular unit, the locking plates were not only glued to the steel plate but some epoxy glue was added to make sure they stay in place. In fact, it's not a bad idea to do this since I recently got a restored Beomaster 6000 back in my work shop for a repair after a damage caused by a power spike. I noted 2 of the locking plates falling of again.

Anyhow, I had to remove the epoxy glue first from all of the 20 locking plates:

After this, the best way to remove the locking plates completely is by given them a short, firm knock with a hammer using a piece of wood. If you try to prime them off (like with a screwdriver), there is a high risk that you damage the key panel. It leaves marks on the top, visible, side of the panel.

The locking plates always have there small pieces of plastic still attached from the injection machine tools. Not really Beolove.....So, I always cut those pieces of.

Once all the locking plates are removed, it's time to get the steel plate detached from the aluminium frame. Most of the time, this is fairly easy done since the glue used at the time did not hold very well. I use a long cutter knife that I stick between the plate and frame. On the Beograms and certainly on the Beocords they seem to have used another type of glue that holds very well (and very difficult to remove...!).

The hardest part is now to get all the old glue removed. I use a flat cutter knife again and some fine grid sandpaper. Followed by an alcohol cleaning.

The most difficult part is coming up now: to get the key panel recoated! As mentioned, the panel is brushed with some coating on top. Those fingerprints are in fact areas where the coating has disappeared over time. Small scratches in the coating do not leave permanent marks. Once the metal itself has scratches, they can not be removed. DO NOT TRY TO SAND THE PANEL. It will ruin the brushed, matt aspect forever....

So, let's remove the coating. A special paint removal (used in the automotive industry) is used.

I always need to apply a few layers of paint removal before all the coating is gone. The chemicals used in the paint removal are dangerous, so take the necessary precautions. They act very fast (10- 30 seconds). A good wash with water and detergent is next. And yes, they shine now........and that is not the way we want it!

We need to bring back the coating. Another difficult task. I've tried different coatings/lackers and again the best is matt/satin clear lacker used in the automotive industry. You need a dust free environment to apply the coating. I looked at how spraying cabins for cars are made and created my own, miniature spraying cabin. It's made out of wood, with a plexi hinged door and a Durst UT100 on top. This Durst is used by analog film photographers to dry there rolls of film pelicule. It has a blower, a heater (with 2 settings) and a dust filter build in. It blows into the cabinet providing a small overpressure with the idea to keep dust out. 

It works fairly well, but still not easy to keep all dust particle out. 

Applying the coating requires some experience. I  have done this like 8 times now, and still make mistakes. This time I put to much coating on the plate the first time and had to redo the procedure of cleaning and coating all over again. 

The coating also requires 24 hours of hardening. I keep the heater on during the first couple of hours on setting 1 (about 40 degr. Celcius). 

This is the result once the whole proces is done. The matt, satin look is back again !

Not bad at all I must say !

Back to the aluminum frame now. Once all the glue is removed from the aluminum frame, it's time to get the black lines repainted on the frame. Some masking tape is used and a fine brush to paint the lines back with matt black metal paint.

This looks a lot better already !

Once the frame is cleaned and the lines repainted, the steel panel plate needs to be glued back on the frame. To make sure that both pieces are perfectly aligned, I made a wood fitting piece. It's important that the gap (1mm) between the key "tongues" and the aluminium frame is correct and the same all along the frame. I use 4 metal plates of exactly 1mm thick as chims. 

With the two pieces well aligned and the glue added, I use a wood plank and spanners to hold everything together until the glue has dried.

While waiting for the glue to dry, I took the FM dial wheel/flywheel spindle through the same procedure.

And 24 hours later, time to check all is OK...

Looks like new (well, almost...)!

All the black plastic locking plates are back in place as well.

And a few more close-ups

We are now getting really close to the finish of this Beomaster 6000 quad restoration. In my next post I'll explain the polishing of the red plexi display panel.

UPDATE !

When I started to put the keypanel  back on the Beomaster, I noticed that the coated surface had a tiny mark on it. This was caused by accidentally touching the surface with glue residue left on my fingers. After doing some further testing I realised that the coating was not very durable. It looked great, but would probably show marks again after some time. This was not to my liking. So I decided to take the keypanel apart again and started to investigate more on the different type of coatings that are available on the market.

First note: the coating that I used so far is a 1K coating (1 component). 2K coatings are more durable since they have a separate hardener that is only activated just before spraying. This, according to my research, is more professional and should give a much more durable coating. My eye's fell on SprayMax 2K clear coat, matt finish. It's hard to find this product in Europe, but finally got a can. The can has 2 compartments: the top with the clear coat and a bottom one with the hardener. The latter is activated by pushing a red button that releases the hardener in the top can. After a good shake, it is ready for use. The disadvantage of this concept is that, once you activate the hardener, you have to finish the can within 24h (depending on the storage temperature).

Another modification I made was in the spray cabin. In stead of laying the panel flat, I mounted it on a stand to keep it vertical. This gives a lot less issues with dust particles settling on the surface (seems logical; why did I not think of this before...). I also raised the temperature of the spray cabin to 60°C after spraying. The SprayMax cures within 10 min, is  dust dry in 30 min and touch dry in about 45 min. The full hardening process takes 24 hours however (at room temperature).

The result was looking as good as my first coatings with the 1K product. I also made a few tests on a spare Beocord key panel (same concept as the Beomaster) and after 24 hours the coating was really very hard. 

This is the end result. Hard to see the difference versus the early coatings earlier in this post. The thickness of the coating is probably a bit higher since I did 2 layers of coating. This was recommended by the manufacturer and was also needed since I did the spraying on a vertical surface. If you spray a single layer to thick, you risk having sagging.

I also coated the spindle off course. Now it's time to glue it back to the aluminium frame. 

This was a little set back, but the aim (remember the title of the first post...) is to get things as perfect as possible !