Beomaster 8000: Step Seven - Replacement of the Speaker Switches with Modern Encapsulated Units and Laser Cut Adapter Plates

The final 'standard restoration task' for a Beomaster 8000 is to replace the speaker switches. My own personal statistics are that in about 50% of all Beomaster 8000s these switches will go bad in the near future if they are used regularly, like for headphone listening etc...They are usually corroded on the inside and frequently when a Beomaster is used again after a long period of storage, they break after a few uses and then the outputs are no longer connected to the speaker jacks. This shows the speaker switches flipped out of their 'compartments' for accessing the solder points:

Note the brown PCB-like base plates that hold the contacts...this switch style has long gone out of fashion in favor of fully encapsulated modern designs that are capable of millions of switchings before they need to be replaced. Unfortunately, these modern switches do not have this base board anymore, and hence they do not fit into the compartments under the heatsink cover. I designed laser-cut adapter plates that mimic the original base plates while snugly fitting the footprint of the modern switches:

This shows them after soldering them in:

And situated in their compartments:

All good now in switch land!

Unfortunately, when I gave this Beomaster a subsequent testing of all functions, I realized that the phono jack in the contact box was broken out and also disconnected. Very beo-unlovely! The next post will report about my repair process of these DIN7 jacks.

Beomaster 8000: Replacing the Speaker Switches with Modern Encapsulated Units and Laser Cut Adapter Plates

After my second round of output PCB troubles in the Beomaster 8000 that I am restoring right now, I put in new speaker switches. The heatsink cover was still off, so this was a 'good moment'. I implemented modern encapsulated switches and laser cut adapter plates that make them fit into the original bays for the switches. A while ago I made a short video about this process, that also shows the laser cutter in action...what's not to like about digital manufacturing methods!:

These pictures document the procedure on the particular Beomaster 8000 that I am rebuilding. This shows the original switches in place:

Here they are 'folded' out and the original mounting plates are visible:

This shows the original switches in comparison with the new replacements and their adapter plates. Note that the here used most recent design iteration has laser etched tabs on the narrow sides of the plates since I was not able to find plexiglass sheets of the same thickness as the original base plates of the switches:

These switches and adapter plates are available to other enthusiasts, just send me a message.

Here they are soldered in place:

This picture shows them held in place in their bays. The laser cut plates exactly fit in the cutouts and the precisely laser etched thickness of the tabs ensures that the switches are at the right height when the heatsink cover is installed:

Beolover 8000: Speaker Switch Replacement with Modern Switches

A fellow B&O fan asked me if my recently developed speaker switch adapter plates for the Beomaster 8000 would be available. I was happy to oblige, but felt like I needed to improve my design a bit for a more satisfying experience. I wanted larger holes for a bit for a better fit of the solder tabs of the switches. I also wanted to cut them from thinner plexiglass to avoid the Dremel step for thinning the tabs for precise fit into the switch compartments of the Beomaster. Another goal was to achieve a press-fit of the adapters onto the PCB board alignment tabs of the switches to avoid the glueing-step to affix the plates to the switches.

Here is a picture of the redesigned adapters with fitted switches (the adapters were cut from 1/16 strain relieved plexiglass):

I also made a video about the process (including a shot of the laser cutter in action - awesome!!..;-). Enjoy!:

Beomaster 8000: Replacement of Speaker Switches - Laser Cut Plexiglass Switch Adapters

I always replace the speaker switches when I restore a Beomaster 8000. They are often corroded, and I experienced several failures in my own Beomasters (I often use my Sennheiser RS180s, and therefore need to switch the speakers on and off fairly frequently...). The issue with these switches is that the original model was designed with a high density board base, which had installation guide tabs on the side. The Beomaster housing is designed with bays that fit these tabs exactly. All new switches seem to be fully enclosed in plastic. While the general form factor is still available, in the past I had to extract the high density boards from the old switches, modify them with a Dremel, and then glue them to the bottom of the new switches. See this post for the original procedure:

http://beolover.blogspot.com/2014/03/beomaster-8000-speaker-switch.html

I never really liked the Dremel job...not precise enough for my taste. Recently, I learned to operate a laser cutter. What better first project than designing a nice adapter plate, which would align the new switches precisely to their compartments??

I cut the adapter platelets from 5/64 plexiglass (this is a bit too thick, but that is all I had at that point). That meant I still had to put the Dremel to them to reduce the thickness of the tab areas to about 3/64, the thickness of the high density board. If I do it again, I will cut the entire adapter board from 3/64 plexi or something similar. This shows the new switches in comparison with one of the old ones and the laser cut adapters. Note the slits, the board mounting guides of the switches fit snugly into them, aligning the switch (BTW: I used No.: 611-S201031MS02Q from Mouser) with the adapters.

Here after glueing the adapters to the switches and Dremeling the tabs thinner:

Here are a few pictures from the installation process:

Original switches removed from their compartments for desoldering:

New switches installed (it surprised me how durable the plexiglass was during soldering...no issues with melting, warping etc...):

In their compartments:

And with heat sink cover installed:

Perfect!! These new switches are much smoother than the old ones and are guaranteed for a few million switchings! On to the display board!