Vintage Products

Re: Noisy Beomaster 2000 - any help?

Dillen — Wed, 23 Jan 2008 16:16:19 GMT

Your capacitor theory could be right, caps can cause the strangest things, but I do feel that a transistor could much more likely be the culprit.

Caps in the signal way are usually there to block DC and conduct AC (the signal) or to keep a point free of AC by decoupling to ground.

In the majority of cases, caps fail by developing leaks or even shorts or by losing capacitance.
Neither of these will normally introduce noise.

A damaged transistor or other semiconductor, on the other hand, can become noisy.
Especially the good old germanium transistors (AC128 springs to mind)
are prone to this but I've seen cases of high frequency transistors (AF and BF...) with this fault as well.

We'll stay tuned so drop a line when you have found out more.

Martin

Re: Noisy Beomaster 2000 - any help?

Stoney3K — Tue, 22 Jan 2008 15:34:07 GMT

Tiny update: My first hunch was correct. Getting the service manual online, and after disconnecting the AF outputs on the receiver board (second flat cable on the number 1 PCB) and the unit gave brilliant silence on all of the inputs. The AF lines must have been leaking HF noise as well and messing up the entire AF signal path. The external inputs work properly again -- at least I have a decent working amplifier. I might take the #1 board out and give it an overhaul when I can make the time for it.

Noisy Beomaster 2000 - any help?

Stoney3K — Mon, 21 Jan 2008 08:52:25 GMT

Our Beomaster 2000 suffered a lightning stike a while back. The unit powers up and all of the touch panel functions work properly, as well as the power amplifier. But... it suffers from a lot of noise on the speaker outputs.

My guess is that the lightning strike may have blown some capacitors which filter noise from the tuner stage to the power circuits, causing that noise to leak (through the power circuitry) over to all of the other circuits.

Have not tried the headphone or tape recording outputs yet. Noise is present on all of the inputs (including phono and tape). Volume, mute and power controls work without any problems, though. The noise sounds like a badly tuned radio (some broadcasts can be heard).

Is my unit dead or can it be repaired, for example by resoldering new capacitors? I don't have the schematics for the 2000, can a B&O dealer help me with those?