Beomaster 8000: Reinstalling Output Amps, Power Supply and Speaker Switches

I now have most of the bottom layer of components restored on this Beomaster. Before restoring the preamplifier and FM tuner boards I want to reinstall the components I have completed so far.

I'll start with the left channel output amplifier assembly. I mentioned before that it is kind of a pain to remove and reinstall these as the board will not fit through the rear opening in the Beomaster cabinet frame. You have to remove the heatsink mounted components, fish them through the opening in the frame, then reattach them to the heatsink.

The reason I remove the components to work on them though is so I can fully inspect them, clean everything properly and have room to work. While the right side is empty I will replace the original speaker switches with Beolover replacements. This is a preventative measure and is a pretty simple replacement when the Beomaster is disassembled like this.

Now for the right channel output amplifier assembly reinstall. You can see how it was easier to replace the speaker switches while the output amplifier board was removed.

I had removed the restored power supply board and voltage regulator assembly when I worked on the rusty cabinet bottom so I reinstalled that assembly next.

Things are looking pretty good. As you can see in the pictures, I removed the control panel door damping component because it was leaking damping fluid. The mounting location for that dampler is cleaned off now and I will be reinstalling a restored damper later.

The last part of this step is to begin hooking up some of the component wiring again. Then it is on to the preamplifier restoration.

Beomaster 8000: Speaker Switch Replacement

Another preventative measure we make on the Beomaster 8000 restorations is the replacement of the Speaker 1 and Speaker 2 selection switches. For this project I am installing a new set of switches that Beolover provided as a kit. It includes two new switches and a laser cut mounting plate so the new switches fit perfectly where the original ones did.

Here is a picture of the original switches.

The next pictures are of the Beolover replacements. It is easiest to make this replacement at this point of the project when most everything else is removed from the Beomaster cabinet.

...and here are the completed switches in their place.

Beomaster 8000: Speaker Switch Replacement

Another task on this Beomaster 8000 restoration is replacing the speaker switches. The replacement speaker switches are another part that Beolover can provide. They have been covered before on this blog here.

Here are the original switches and new switches side by side.

Here is the speaker switch wiring side of the original switches.

This picture shows the new Beolover replacement switches soldered in and ready to use.

Tomorrow I will get the restored preamplifier board re-installed and this Beomaster should be ready for a quick test. I would like to check the Beomaster power supply voltages and get the output amplifier boards adjusted (DC offset and idle current).

Beomaster 8000: Replacement of Speaker Switches with New Encapsulated Ones

Today I opened up the back of the Beomaster 8000 to replace the speaker switches and then do the big reservoir capacitors for the outputs. Replacement of the speaker switches with modern ones requires the use of adapter plates since the original switches are no longer available. Last year I designed suitable adapter plates that can be laser cut. I made a short video about the entire process. It can be found here. I improved the design in the meantime by thinning the far ends of the plates using laser raster scanning. That ablates the plates to a perfect height and they fit a bit better into the compartments when the heat sink cover is installed. Here is a picture of the new switches with plates in comparison with one of the old switches:

The following pictures are from the exchange procedure:

Old switches from top:

and from bottom. The old PCB style bottom plates are visible. The compartments are designed to fit them. They need to be replaced by the laser cut adapters:

The new switches after soldering them in:

And after seating them in their compartments. A perfect fit! This is Beolove...;-)!

On to the reservoir caps while we are back in there!