Thank U for your interest. I think the relay does not hold a voltage flow. Sometimes after 2 seconds, sometimes after 2 minutes, and another time after 2 hours, the relay disconnects. Then it's usually not possible to re-enable B&O. I mean it turns on, but after a second or two I hear the relay clicking and B&O goes into standby mode. Now I noticed that B&O had a set input voltage of 240 V, and in the network I have 230 V. Should I switch the voltage to 220 or does it not matter, because there is some tolerance range? Besides, the relay is running at a constant voltage, right? Xavier P.S. As I mentioned, I've very poor knowledge of electronics. I would be happy to return the device to the service, but in my area no one wants to undertake diagnostics. Only one electronics has tried and said he could't find the cause of the fault...

Hello! I've had B&O 7700 for several years and the relay in the power section has broken. There are no relay parameters on the dust cover, only the model: PASI manufacturer, relay model KS/R-01-C. I'm weak from electronics and I cannot find the parameters of this relay in the electrical diagrams. Can anyone help me find the parameters of the relay to find the right replacement? I'll be grateful for any tips. Xavier

The fact that the relay does activate even for a short time does not mean it’s broken but that it is losing its 6.5 volts. This will take some technical skill to fix and the service manual is online so it does not require a B&O service tech. How comfortable are you with using a multimeter and desoldering/soldering parts on a PC board?

I know how to use both :) I soldered the relay by myself. But I don't want to resolder it again. I'll put on a new one with the right parameters. Need to buy relay with 6 V coil and the current of 1 A, right? I've got electrical diagrams for beocenter 7700 :) What You sugest next? Xavier  

First you need to confirm that your standby voltages are fine. TP9 should read 6.5v DC. You should also have 5V DC at pin 5 of the P11 connector. If those are fine, then you likely have a fault in the power amp section that is muting the unit. There is no need to replace the relay as what you have observed is its normal operation. Finding a fault in the power amp circuit is more difficult since the +/-30v supplies share the same board and there is no easy way to disconnect the power from one channel without pulling the output transistors. Since you are able to get it on for a time, I would try looking for a DC voltage on each channel w/o speakers connected while the relay is engaged and figure out which one is tripping the fault circuit as a start. This all assumes the 6.5 and 5v supplies are fine.

Okay, thank you very much. I hope I understand and handle it :) However first I've to buy a new relay, because the old one is in small pieces and I am not sure if they're all. Besides, the thin copper wires from the coil are broken. But I hope that knowing the operating parameters of the relay I'll easily choose the right replacement in the local store today. Later, after installing the relay, I 'll do voltage diagnostics, as you suggest, and I'll inform you about the results. One thing. I'm not sure what You mean, but the beocenter switches off completely - doesn't mute.

By muting the unit I meant going into standby. The relay does not switch all the power off.

I thought so :) I already have a new relay. The seller said that it should fit after a small modification - two legs are unnecessary. But here it's midnight and I'm tired after work, so I'll run B&O for diagnosis tomorrow evening. Greetings from Poland! X

Sorry, but a lot of work and Easter. I had no time for pleasure in recent days... After all, today I installed a new relay to do the diagnostics you wrote about, but after plugging into the power supply, there is no reaction. I found a burned fuse. I don't know when and why it burned down. Anyway, I need to buy a new fuse now. Slowly in small steps forward :) X