Reply To: Beomaster 4400 – Sudden drop in sound?

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Check those lamps. Correct voltage lamps is not enough. The important thing is the current draw and their “working pattern” with varying voltages. Does the voltage on TR7 base also change? Or is it coming from IC1? Martin

Hmmm. I don’t understand why the lamps are so important. With a load of pain I was able to remove the 2 tuning lamps. They are just regular lamps. I changed them for a different pair (tried everything from 6v – 12v at 30mA) but the issue is the same.

I don’t think the issue is with the lamps or does b&o use some super duper special lamps? Can’t see why, service manual also seems clear in the lamps needed.

Something is triggering the mute circuit and it mutes literally everything. I will pull those transistors from the circuit first now, see whether they still hold up.