Beomaster 8000: Step Three - Replacing the Main Reservoir Caps

No power supply restoration of a Beomaster 8000 is complete without also replacing the four big cans in the back. They are the reservoir capacitors for the output amplifier ±54V power rails. One 10000 uF capacitor per polarity and channel - massive! That gives the Beomaster 8000 its excellent output stability at 150W per channel. Awesome!

Here are a few impressions of my process:

This shows the original capacitors on the right side:

I unsoldered and pulled them out and replaced them with modern 105C grade Japanese units. As usual, modern capacitors are a bit more compact than 1980s types. That is why I use 3D printed adapters to fit them into the capacitor bays of the Beomaster 8000. This picture shows the original capacitors and the modern replacements with their 3D printed adapters:

The adapters and capacitors are available as a kit, just send me a message using the contact form on the right

After the installation it turned out that I broke off one of the resistors at the thermal switch for the right side:

This happens frequently when pulling out the capacitors, since the resistors are in the way, and they cannot take much bending. I replaced both resistors with new ones:

Then it was time to turn this 8000 around and do the left side:

After replacement:

After this I measured the capacitance of the original caps and of course they were out of spec (they usually are at this point):

4000uF is less than half of the specced 10000uF, but this would still have worked at moderate volume settings. But of course, the caps would have failed in the near future. So it was the right thing to replace them now for piece of mind. 

An then it was finally time to turn this Beomaster 8000 on for the first time:

And of course, one of the segments in the input display was a no-show. No problem, since I usually rebuild these displays anyway with SMD LEDs to ensure stability in the years to come. These displays all will fail in the near future, i.e. it is almost better to buy a Beomaster with failed display for less money and then fix it. That way one has a Beomaster with displays that will likely last another 30 years.

On to recapping the rest of the unit!