Beomaster 8000: Boxing Up for International Shipping

My experience with the shipping of Beomaster 8000s is such that one should basically never ship them single boxed (see recent single box mishap here). The 47 lbs weight of the units makes double boxing with thorough foam padding with industrial grade foam necessary. I use new foam and boxes whenever I build a shipping container. In fact, I am thinking I will refuse return shipping without a second box from now on. Single box shipping is penny-wise but pound-foolish. Maybe a $30 difference in materials. Yes, quality foam is expensive, but worth every penny if you Beolove your Beomaster 8000. Anyway, here we go:

International shipping requires typically a box with a smaller volume weight of 108 inches (i.e. circumference x length <= 108 inches). These parameters need to be kept in mind. Otherwise it will get complicated since either juicy oversize charges apply or freight must be used (depends on carrier).

Luckily the Beomaster 8000 fits into a 12x24x36 box with an inner box size of 10x20x30. Add two full size 1" poly foam sheets (~72" x 80") and a few scraps of cardboard for additional impact shields and we are good to go. Here are a few impressions of my effort with a Beomaster 8000 that I am shipping to the UK tomorrow:

I start out with a double strength corrugated cardboard 12x24x36 box. Then a foam layer:

Now it is time to place the inner box. Since I was not able to procure double strength 10x20x30 boxes, I put two single strength boxes inside each other. This creates a very HD inner box. Then another two foam layer into the inner box:

Now it is time to build the foam layers around the inner box. Two layers on the long and three layers on the short side.

I layer the foam with additional cardboard pieces to add more impact protection. It also helps to push the foam all the way down:

Now add a Beomaster 8000! A last look

And then it gets wrapped in a layer of thin cushioning:

After putting it in the inner box, more foam is layered around it. Two layers on the long sides and one on the short. So we have a pretty uniform foam layering on all sides once all foam layers are added up between the two boxes.

Now it is time to fill the wedge shaped space above the Beomaster:

Wait! I was able to supply a pristine looking Beolab Terminal remote for this Beomaster. 

Now is the time to add it. I cut out a window for it in one of the foam pads that go on top of the Beomaster:

And the final layers

and one more on top:

Time to close the inner box:

Add another layer of cushioning. Unfortunately, there was not enough room for a full inch of foam, so I had to use a 0.5" styrofoam panel. This should work.

Add a full roll of packing tape to protect the corners and seams, and an expensive international mailing label and customs forms in quadruplicate and we are good to go!

Farewell my lovely! May the postman be gentle with you! This is Beolove!

Beomaster 8000: Replacement of the Speaker Switches

The final step of my current Beomaster 8000 restoration was to replace the original speaker switches with new encapsulated ones. Due to the encapsulated construction the new speakers do not have the PCB style base plate that is used in the Beomaster to align them with the small compartments that holds the speaker switches in place. I recently designed some laser cut adapter plates that fit the new switches. More information about this procedure can be found in this blog entry.

Here are a few pictures of this procedure:

This shows the original switches removed from their compartments and turned around:

New switches and adapter plates installed:

And new switches installed in their compartments with the heat sink cover back on:

This concludes the restoration of this Beomaster! Now I will test it for a while in my Beosystem 8000 to make sure there are no loose ends.

Beomaster 8000: Display Repair (III) - Rebuilt Displays Installed on PCB, LED Replacements for the Indicator Lights, and a Broken Transistor

Another 24hrs test of the rebuilt Beomaster 8000 displays passed without incident. So it was finally time to put the displays back on the board and test them in the Beomaster. I also replaced the indicator light bulbs with my latest SMD LED replacement boards. Here is a picture of the boards. They fit directly into the indicator cabinets as a drop-in replacement for the light bulbs:

Some more detail about these boards is given in an earlier blog entry, and a YouTube video.

This photo shows the full glory of the display PCB after everything was put together. The covers of the indicators are off, to show the LEDs:

And here with the red covers on:

There was a bit of an excitement during this effort, since at first the 'clipping' indicator would not work properly after I replaced the light bulb with my LED assemblies. What happened was that the LEDs would not go off if there was no clipping. In effect the LEDs behaved as if I had not removed the collector resistor (R40) from IC4, but I had. So something was fundamentally wrong. The plot thickened when I measured the base voltage at IC4 when clipping was on: I only got 0.6V, while it should be 1.2V since IC4 is a Darlington transistor where two diode drops occur between base and emitter. IC4 is right above the clipping indicator cabinet:

This suggested that one of the transistors in the Darlington had a significant problem. The next test was to connect the base of IC4 to ground. If the transistor is o.k. the LEDs should have gone off, but they only reduced their intensity somewhat. All this suggested that IC4 was damaged. I replaced it, and then everything was fine. 

This leaves replacing the speaker switches in this Beomaster, and then this restoration will be complete.

Beomaster 8000: Display Repair (II) - Assembly and Test

After a 24 hrs 'burn in' in my test fixture, I reassembled the Beomaster 8000 displays using my latest method to fix the red covers back to the PCBs. I now really like using hot glue for that. It can still be removed without much of a trace if one ever needs to get back in there, while making a pretty strong bond. And from the outside of the Beomaster the glue is not visible due to the bezel underneath the glass panel:

I usually run them for another night after glueing them back together, just to make sure that all than handling did not cause any trouble with the solder bonds of the LEDs:

Tomorrow, I will put them back on the PCB and also replace the incandescent light bulbs of the indicator lights with LED assemblies.

Beomaster 8000: Display Repair (I) - Intermittent Display Segments Replaced with SMD LEDs

The Beomaster 8000 that had the flipped Tape inputs, also had some intermittent display segments. It seems there are two stages of display death. First the segments go intermittent. Often they still work once the Beomaster has heated up, but they blink once in a while...not very pretty. So we decided to rebuild the displays with SMD LEDs. First I took the display PCB out:

Then I unsoldered the displays and removed them. It is best to do all at once. That makes it much more straight forward to take them out from the board:

Then I opened them up:

Here is a picture of the frequency display with the original LEDs still on there. They are not encapsulated, and this is the problem. The small bonding wires detach over time, and that causes the blinking and final disconnect of the LEDs. 

This shows the same board after replacing the LEDs with SMD packages:

I did this to all four displays. Now they are running for 24 hrs in my test fixture to make sure that everything is stable:

Tomorrow, I will put them back together and then test them for some more time before putting them back into the Beomaster.

Beomaster 8000: 3D Printed Control Panel Lid Damper Arm

This is a follow up to an earlier post, where I encountered a cracked control panel lid damper arm. In the meantime I was able to replace the broken part with a 3D printed replacement. I made a short video about this process:

Here are a few high res pictures:

The broken arm:

The 3D printed replacement installed. It was printed on a Stratasys uPrint to achieve the necessary precision. It needs to fit snugly on the damper shaft, and the 'hook' that connects to the linkage needs to have the correct diameter to prevent disconnection of the linkage:

and inside the Beomaster:

Beomaster 8000: The Mystery of Swapped Tape 1 and 2 In- and Outputs and a Broken Damper Arm (Sad Story)

A Beomaster 8000 that I recently restored showed a strange phenomenon when I hooked it up to my Beogram 8000 and Beocord 9000 for in-situ testing: When I pressed start on the Beocord, the Beomaster came on with the Tape 1 input selected as it should due to the Beolink connection between the two. However, there was no sound from the tape (and no recording either as I found out shortly after). However, I was able to hear the playback signal very faintly when I cranked the Beomaster up to full volume. This indicated that there was something fundamentally wrong with the Tape inputs. The plot thickened when I hooked my iPad up to the Tape 1 input and only got sound out of the receiver when selecting Tape 2. Then I connected it to the Tape 2 input, and, you guessed it, I needed to select Tape 1 to be able to listen to it.

It appeared that the inputs were swapped...very strange!

The Beomaster went back to the bench, and I opened it up. Then I traced the signals to plug P3 on PCB3 (preamp). And indeed both in- and output leads were swapped on this plug, effectively connecting Tape 1 to the Tape 2 connections on ICs 202/102, while Tape 2 was connected to IC4.

I removed the terminals from the plug housing and replaced them in the correct order. I made a schematic for future reference:

After this I thought everything was fine, and I tested the inputs. And indeed, now I plugged in the source to Tape 1, and it played when selecting Tape 1 as input. The same for Tape 2. Great! (I thought!). But then I played with the 'input level presets' (potentiometers accessible from the outside of the Beomaster that allow to attenuate the inputs if a signal source is too strong). This yielded another surprise: Now the Tape 2 presets affected the Tape 1 input, and the Tape 1 presets affected the Tape 2 input...very strange! But of course much better than the original situation where I was not able to use my Beocord properly. Still strange!

After scratching my head a bit, I remembered that some Beomasters come with a different connector box, where the tape RCA connectors are connected to the Tape 1 input instead of Tape 2. At that point it dawned on me what probably happened to this Beomaster 8000 of unknown ebay provenance:

The previous owner swapped the original input box that had the RCAs on Tape 1 with an input box  from an other Beomaster that has the RCAs on Tape 2, and it seems that these two configurations have Tape 1 and Tape 2 swapped on P3 that connects to the circuit board.

Here is a pic that compares the two boxes and shows their P3 terminal arrangement:

Note the different arrangement of the Tape in and out RCAs on top and the input level presets labeled below. Tape 1 and 2 are swapped. At this point it escapes me why B&O would have changed the P3 pinout...there is really no reason, they could just have connected the RCAs to Tape 1, relabeled the box and been done with it.

It is interesting to note that all Beomaster 8000 circuit diagrams that I so far have seen show the "standard configuration", but there is a significant percentage of Beomasters that have the "RCA on Tape 1 configuration"...

Anyway, this Beomaster is working now as it should (as long as one remembers which input level presets to use) and my Beocord works happily with it.

Some bad news: While putting the left side of the Beomaster back together after rearranging the inputs, a 'petit malheur' happened: When I bolted the control panel lid back onto place, and closed it a loud crack occurred, and then the lid was undamped. first I thought the linkage broke, as it has before, but no, a more spectacular problem arose:

The damper arm cracked into two pieces:

This picture shows the arm fragment still attached to the linkage with the broken off part:

Here is a shot of the two cracked parts assembled with the damper:

And the broken arm separately:

I guess it is time to fire up a 3D printer...;-). Small parts like these are an interesting printing challenge to get the proper fit and stability. Stuff for another blog entry.

Beomaster 8000: Volume Wheel (Encoder) Damping - 3D Printed Paddle Wheel

This is a follow up to my last blog entry about restoring the damping of the Beomaster 8000 volume wheel rotation. Often, the volume encoder looses all its damping over time, which can create an unpleasant situation when someone uninitiated to the issue accidentally cranks up the volume to 6.0 because the volume wheel does not stop spinning.

My latest solution involves a 3D printed 'paddle wheel' that press-fits on the volume encoder shaft. Together with a more heavy duty high viscosity damping grease, the Nyogel 767A a very smooth purely viscous damping effect can be achieved. I made a short video about the new part and its installation:

Here is a better picture of the part (printed with a Form 1 stereolithography printer):

Beomaster 8000: Replacing the Reservoir Capacitors

I finally received the 3D printed reservoir capacitor adapters for the Beomaster 8000 that I am currently rebuilding. So I set out to install the new capacitors as final step of the full recap of this unit. Here is a picture of the Makerbot II printed adapters together with the new 10000uF capacitors (105C power supply capacitors made by Nippon United Chemi-Con EKMH630VSN103MA50M):

These adapters give the modern, 35mm x 50mm capacitors the proper size to fill out the compartments of the Beomaster. For installing new reservoir capacitors the Beomaster needs to be dismantled substantially:

Once access is enabled, the procedure is fairly simple: Unsolder the old caps, and put the new ones in. Here are the pics of the right channel. Before:

and after:

And the left channel. Before:

and after:

And this concludes the recap of this unit!

While I waited for the 3D printed adapters, I fixed the broken out left hinge of the control panel cover. Luckily the fragment did not get lost...I glued the broken out piece back into place with epoxy glue. So far this seems to hold up fairly well...only time will tell if this really worked and whether it will survive shipping to the UK. Here is a picture of the glued-in fragment:

Beomaster 8000: The Recap Continues

I continued recapping the Beomaster 8000 that sits on my bench right now. I rebuilt the filter and tone control PCB that sits underneath the control panel, the two tuner PCBs, and the preamplifier board. As usual, I used quality Japanese 105C capacitors. I also cleaned all board connectors with a fiberglass brush to remove oxides, and then I coated them with DeoxIT D100L to protect them from future decay. Here are some pictures of the boards before and after:

Filter and tone control PCB before:

and after:

Tuner boards before:

and after:

and a detail shot:

And the preamplifier board before:

and after:

and a detail shot:

On to the main reservoir caps for the outputs!