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I made good progress with the restoration of the Beogram 4004 (Type 5526) that I recently received from a customer in California. Until I came to the part where I adjust the floating chassis and align the platter etc...what is usually a tedious, but fairly straight forward process quickly turned sour with this unit, giving me fodder for another post in my 'when disaster strikes' series!...;-):
What happened was that when I tried to adjust the height of the three leaf springs to get the floating chassis level, one of the adjustment bolts ripped off. I thought it was turning a bit difficult, but in this case it turned out that one of the previous owners had epoxied the nuts to the threaded sections of these bolts. Since I usually use a ratchet with a nut to turn these screws, I did not see that I was actually twisting the bolt and not just turning the nut!
This shows the assembly before the disaster struck (luckily I took a picture after straightening out the grossly bent alignment pins for the aluminum cover plates). The bolt in question is behind the pin to the right:
This is the section that came off:
After removing the leaf spring it looked like this. The bolt had separated at a level flush with the threaded hole in the enclosure bottom. Pretty Beounlovely!!:
At least, after heating the bolt with my solder station blower I was able to get the nut separated from the bolt fragment:
The next step was dealing with the broken off bolt fragment that sat flush in its threads. Such twisted off bolts are dreaded by anyone how deals with mechanical things! It is usually a bit of a mess to deal with such bolts. Since I only have a mini drill press for delicate tasks, I opted for drilling the M4 bolt out in three steps. First I made a mark with a center punch as centered as possible on the bolt surface. Then I used a 2 mm drill to hollow out the bolt. I used some oil to prevent the drill from getting stuck:
The next step was re-drilling the hole with a 3 mm drill:
And then I finally went in with a 4mm bit. This cleaned out all the remnants of the bolt:
Then I Installed a M4-45mm stainless steel flat head bolt with a nut and a washer:
This was possible since the mounting posts for these adjustment bolts are hollowed out and accessible from the bottom of the enclosure. The flat head of the bolt fit perfectly and flush into the hollow:
And this is how it looked with the spring installed again:
A while ago I received a Beogram 3000 with a deteriorated plexiglass hood. The plastic mounting brackets of the hood were broken out
and one of the plexiglass hinges was broken off:
I developed a repair kit containing 3D printed mounting brackets, a special tool for re-inserting the spring tensioning block, and laser cut plexiglass patches for rejoining the hinge:
The video below shows how to use the parts. Like all other Beolover parts, this repair kit is available to other enthusiasts. Just send me an email or use the contact form on the right. Enjoy the video!
Oh well...Beoloving can be a bit experimental. When new parts are developed occasional failures need to be anticipated. So it was the case with the part that I designed last year to repair a control panel lid spring retainer when I restored a Beomaster 8000. This part failed during return shipment, maybe due to the package getting a bit hot and my plastic part a bit soft, which let the spring 'escape'. This is how it looked when I received this unit again about a week ago:
To finally cure this issue for good, we decided to purchase a Beomaster unit from ebay. A unit with a badly damaged heat sink became available:
Seems a fork lift drove through it or a similar disaster happened. Miraculously the control panel lid was still intact without any damages. While convenient for the issue at hand, it always hurts to see a Beomaster 8000 go down like this due to carelessness or poor packing for shipment.
Some more parts from this unit turned out to be useful to cure some more cosmetic issues with this unit like the scratched 'Monitor' button
When I put the unit back together after these repairs, it occurred to me that the lid made an ungainly clonking noise when opening. It turned out that the control panel lid linkage that connects it to the motion damper was shifting abruptly from one side to the other in the fixture that connects it to the lid during the opening sequence. I took this as an invitation to improve my 3D printed replacement linkage by making the upper end a bit thicker, so that it fits precisely into the allotted gap, preventing the shifting issue:
I installed it (shown a prototype printed in red for more detail):
After verifying that this cured the issue I replaced it with a black 'production' part since the upper end can be seen when the control panel lid is open:
This linkage, like all my parts, is available to other enthusiasts. Just send me an email or use the contact form on the sidebar. There is also a video on my YouTube Beomaster 8000 playlist that demonstrates the installation of the linkage.
All good now in the control panel section of this Beomaster! Time for a little test-drive before shipping it back!
When I set out to do the sub-chassis, platter and tone arm lowering adjustments on the Beogram 4002 (5513) that I am currently rebuilding I realized that the larger aluminum plate was not seating properly with the plinth pushed back. If that happens it is impossible to properly adjust the platter to be flush with the plate.
The plate was wiggling up and down in the back left corner where one of the locks that are supposed to pull the plate down onto the frame when the plinth is moved back did not do its job. The locks accomplish the pull-down with a leaf spring that is attached to the bottom of the lock plate. This shows the right-back lock that still has the leaf spring attached.
I thought a bit about how to fix this, and I know that many Beograms either never had the springs or they fell off at some point and were discarded. In these cases often a tech bent the lock plate to act as a makeshift spring itself. Now in this case since the other three lock plates still had their springs attached, I did not want to bend just one of them. Somehow this did not feel Beoloving enough. So I came up with this fix:
A 3D printed wedge that fits to the bottom of the lock plate:
I glued it to the bottom of the plate using double sided tape. I always try to do things in a reversible way in case someone comes up with a better fix in the future and wants to remove my fix.
When I put the aluminum plate in and pushed the plinth back, this wedge very satisfyingly pulled the plate down to where it should sit. All good now with this plate lock! No detail to small for my attention! This is Beolove! On to the platter and sub-chassis adjustment.
On the way to the perfect Beogram 4000 I realized that all 4000s that I so far encountered did not have the hood mounting screw springs that the later Beogram 4002 and 4004 have. These springs conveniently push up the screws making it really easy to take off and replace the hood of these turntables. I checked the service manuals, and indeed the Beogram 4000s do not have these springs included. I guess B&O practiced kaizen here and gradually improved their designs (even though I disagree with the change to DC motors and the implementation of the retro analog control system on the 4002/4 models - the 4000 is much more advanced in this department - I'd love to meet this designer for a chat if he is still around). Anyway, a Pilot G-2 07 pen donated a spring to the Beogram 4000 that I am currently restoring, which I cut in half and installed on the two bolts. I made a short video about the process. Enjoy:
On to doing the final adjustments of the platter height, and then there is the polishing of the scratched hood...this means a nice workout is coming up in Beolover's garage!
After performing all necessary restoration tasks on the Beogram 4000 that I restored during the last few weeks, I put the aluminum panels back on. I quickly realized that the platter was not flush nor centered relative to the surrounding aluminum panel. This meant I needed to adjust the chassis and platter positions. The service manual prescribes to adjust the platter first relative to the chassis, and then adjust the chassis poison relative to the enclosure, i.e. the aluminum platter surrounding the platter to create a situation where the platter is flush with the panel and also centered in the opening. In other words the task was to achieve a Beoloving situation where the Beogram looked just perfect!
I made two short videos describing the the process. Here is the first one, that describes how to adjust the platter relative to the chassis:
After the platter is adjusted the chassis can be aligned. This procedure is shown in the second video:
Well, this pretty much concludes the restoration process. I am almost sad, since I really got used to this most beautiful piece of engineering, and I will have a hard time to let this Beogram 4000 go back to its owner! I am grateful to Jacob Jensen for coming up with such wonderful designs. They enrich my life and they also got me turned on to electronics. It has been a wonderful experience the last few years! Of course I never met him, but it feels like I just lost a friend! Rest In Peace! It is Beolove!
The last Beomaster 8000 that I renovated came back to my bench after suffering shipping damage on the way home to its owner. There were some broken traces on the uProcessor board and a broken out button PCB in the control panel). After I fixed these issues and put it back together, I set out to write a proud email to the owner announcing the swift return of this Beomaster, this time double boxed. A few seconds after I hit the 'send' button, a loud crack happened and a piece of plastic ricocheted past my head. This is what I found. One of these pieces was located on the other side of my work shop:
First I did not quite understand what happened, but then I realized this part must have originated from the Beomaster that sat on the bench next to me! I looked around and found this situation on the back of the control panel lid:
The spring that opens the control panel had broken out of its plastic retainer and the lid hung limp on its hinges. No more springy opening after pressing the bar. This spring is surprisingly strong, and while the lid is closed it stores the energy needed to open the panel. This energy released creating a projectile.
First I asked around if anyone had a decent condition lid (3D printing still has 'finish issues; it is difficult to produce good lucking parts for exterior repairs), but I came up empty. So I further examined the situation and came up with a low impact strategy to fix it. Dillen of Beoworld.org advised me that the plastic bar that holds the spring mechanism can be slid out to the side of the lid. I opened the Beomaster up again and extracted the lid. Then, indeed, the part easily came out from its groove revealing that it is hollow. This opened up a route to a 3D printed fix. Here is a picture of the part that I had printed on a Stratasys uPrint printer in ABS:
I only had access to white filament, so I had to paint the part black on the visible areas. This part fits precisely into the gap in the plastic part and over the spring:
Fully inserted:
Then it was time to test the part under stress. I slid the bar back into the lid:
Then I put everything back together. Here is a view of the Beomaster from the back:
Not too bad...hardly visible, and if one does not know how it is supposed to look, one could almost think this is how it was designed. The Beomaster went back into my Beosystem 8000 to play with its old friends the Beogram 8000 and the Beocord 9000. I want to give it a few days of testing to make sure the shipping damage has been remedied in a stable way before I ship it out (this time double boxed...this experience demonstrated that an original B&O box is just not enough protection for today's shipping environment.
The final challenge of my current Beomaster 8000 restoration project was to restore full functionality of the control panel cover. When I received the unit, the aluminum cover had lost its spring action, i.e. it would just loosely sit on top of the control panel by means of gravitational forces. In pristine condition, the panel is held down by the plastic lock which fits into a small cutout in the side of the aluminum panel. When pressing 'programming' on the bar between the cover and the lower body of the receiver, the lock releases the panel and it opens at a measured speed, controlled by a motion damper situated below the control panel to which it connects via a acrylic linkage.
In the present unit, the control panel cover lock was mutilated by Mr. Amateur for a reason only known to himself, i.e. it was not able anymore to hold the cover down. He cut off both ends of the small plastic part. Here is a picture of the sad condition of the lock as I found it:
So, the first step towards restoring the full functionality of the cover mechanism was to reproduce the lock part via 3D printing. For this I extracted a pristine lock from one of my three Beomaster 8000s and took measurements. Then I had it 3D printed on a Stratsys uPrint. Here is a photo of the printed part in comparison with the mutilated original:
This video discusses the process of replacing the lock:
Unfortunately, Mr. Amateur also disabled the spring mechanism of the cover so it would not open up with the mutilated lock not holding it down anymore. To 'achieve' this he removed the metal plate that holds the spring in place in the back of the aluminum cover part, which released the spring and let the cover fall down freely. This is shown here (the wire loop that sticks out needs to be secured within the plastic body of the panel underpinnings to generate the spring force):
Since the original metal plate was lost, I cut a new metal insert from a piece of galvanized steel sheet, and pressed it into the slot. This reactivated the spring mechanism, and the cover would open again by itself when released from the lock:
The next step was to restore the damping mechanism. Mr. Amateur disconnected the linkage from the damper at some point and then must have tried to reconnect it, but he did not understand how to reinsert the lower end of the linkage into the arm of the damper (just put the damper arm vertical, and slide the linkage from the right side over it - the gap fits the protrusion on the arm in that position...live and learn...;-). So he opened the gap in the linkage (apparently by slightly melting the linkage over a flame or similar) in an attempt to stick the linkage back on the arm, but this resulted in a situation where the linkage slipped off the damper arm by itself due to the enlarged gap whenever the cover is closed. I fixed this by exchanging the damaged linkage with a 3D printed replacement, which I designed a few months ago for another Beomaster 8000 restoration where the lower part of the linkage was broken off (see here for a description of this effort). Here is a photo of the 3D printed replacement in comparison with the damaged original:
And here installed on the cover:
The action of the restored control panel cover is shown at the end of the above video. Now this Beomaster 8000 will be tested embedded in my Beosystem 8000 in its fully restored glory for a couple weeks under 'real life conditions' before it goes back to its owner (to make sure that there are no loose ends under the hood - these complex units tend to have intermittent issues, that often only manifest themselves after a using them for a while)
