Very common is a corroded Mute relais. Replace it or clean it.

Hi Die_Bogener,
Thank you for the tip !

I forgot to mention that I already did a full restoration of that Beomaster a few years ago, which included replacing the relays, so I know the relay is good.
(btw if you do so, make sure you use Cadmium plated relays for the power supply relay, newer, Non-cadmium relays really don't last long with the inrush current).

Also just moving a bit the speaker plug in the connector is usually enough to get it working back, so it really behaves like a connector fault.

pilotomic:  I had a similar issue with a different model Beomaster. The pins in the speaker connectors were worn to the point that they didn't make good contact. I was not able to find the same style connector as a new replacement. My solution was to buy a different style, board mounted, speaker connector and swap the pins from the new connector into the original connector.

Another possibility is to remove the pins from the old connector and squeeze the pin tips together. I would see this as more of a temporary solution.

I probably have some pictures that would make the above descriptions make more sense. Let me know if you need any additional clarification and I'll try digging through my photo archive to find them.

As far as the mute relay goes... Do you have any idea why B&O would only mute Speaker1 and not Speaker2 in the BM5500?

Glitch

As far as the mute relay goes… Do you have any idea why B&O would only mute Speaker1 and not Speaker2 in the BM5500? Glitch

Because the Spkr 2 socket is designed to supply Link Rooms via the MCL2 system, hence when pressing Mute you only want to silence the main room.

Guy:  That explanation makes sense. Thanks!

pilatomic: I found a similar speaker connector on my bench. A picture of one of the pins is shown below. HTH.

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Glitch

Glitch : I already tried to squeeze the pins together without taking the connector appart (using small pliers), it seemed to help temporarily, but not for long.

Thank you for the picture of the pin. I'll look for potential replacement connector, but this type of speaker socket has been out of style for quite some time now, not sure if some PCB-solderable parts remains.

FYI, that particular pin came out of panel mount, 2 pin DIN, female connector. These still seem to be reasonably easy to buy, but are of questionable quality. I agree that finding a NOS solder-able part is a long-shot, but I've been surprised before by what I've found for sale. I think that any possible solution is going to involve creativity, ingenuity, and some quality time with jeweler's files.

Trying to look at the bright side, the pins from the panel mount connectors have the right the "business end". The material between the pin fork and what gets soldered to the board is less critical.

On a similar subject, I've been thinking about replacing the 3 and 4 pin DIN speaker connectors with "something else". Considering that the male versions of these connectors are essentially unobtainable, there appears to be a need here for those that are trying to keep the old equipment going. I assume that I'm not the first to consider this. If a solution exists, it would also solve the worn-out 2 pin connector dilemma.

Glitch