Vintage Products

Re: Beomaster 900K mutes itself

tournedos — Tue, 22 Sep 2009 00:39:42 GMT

No problem Jeff - you need to get something older so you can tap as well

Re: Beomaster 900K mutes itself

burantek — Mon, 21 Sep 2009 15:51:43 GMT

Dillen:
The BM4400 does not have AF transistors so is not prone to
this type of failure.
It will have to be something else. A cracked solder joint, a heavy tuning
drift outside of the AFC reach or some muting fault.

ARGH!

Sorry for the red herring Mika! ...and I was all fired up to go tap-tap tonight!

I guess at this point, I'll lean toward a cracked solder and have a look around when I have a chance... I'll put it on the "back burner" until then, as I was hoping it might have helped Mika and myself at the same time.

Dillen:
Yes, that's the whistle.

Ah! Thanks for the confirmation, Martin!

Re: Beomaster 900K mutes itself

Dillen — Mon, 21 Sep 2009 15:45:42 GMT

The BM4400 does not have AF transistors so is not prone to
this type of failure.
It will have to be something else. A cracked solder joint, a heavy tuning
drift outside of the AFC reach or some muting fault.

Yes, that's the whistle.

Martin

Re: Beomaster 900K mutes itself

burantek — Mon, 21 Sep 2009 13:11:41 GMT

Hi Mika/Martin,

I have exactly the same thing that happened to an immaculate BM4000.

Turn it on, tune a station -perfect, then after a while... click, nothing!

Reboot, try again, plays fine for a while then... click again.

I never got in to look around, but was leaning towards the IF FM tuning. I would be very interested to hear how you get along with this. In the meantime (when I get a chance) I will open it up and try the tap trick!

On another note, pardon my ignorance... but is there a proper technical term for (let me try to decribe it)... Say you're tuned into an FM station, and particularly with some treble dialed in, you get a faint background variable whining... almost sounds like frequency tuning? It does not exist on any other sources. Some sort of interference between the tuner/power supply?

edit: Heterodyne whistle?

Thanks in advance,

Re: Beomaster 900K mutes itself

Dillen — Sun, 20 Sep 2009 09:32:04 GMT

Yes, most likely one of the IF transistors.
Of course, there could be many other reasons but that would be my first try.

Martin

Re: Beomaster 900K mutes itself

tournedos — Sun, 20 Sep 2009 05:42:46 GMT

Thanks. The problem may take days to surface, so this will have to wait until winter when I bring it home from the summer house and can keep its guts permanently on display

So you support my theory of some transistor shorting internally? I have two more 900's so I could of course try to swap stereo decoder boards to further isolate the problem... the problem must be before it or in it as both channels go silent.

Re: Beomaster 900K mutes itself

Dillen — Sun, 20 Sep 2009 01:35:40 GMT

Try tapping the AF transistors gently with f.e. the handle of a screwdriver
next time it mutes.

Martin

Beomaster 900K mutes itself

tournedos — Sat, 19 Sep 2009 10:25:12 GMT

I have a nice, otherwise well working Beomaster 900K. Every now and then, usually after extended play, it decides to mute itself. Lights stay on (so not a problem in the power switch), but nothing comes out of the speakers. If I turn it off and straight back on, it always continues to work as if nothing happened, so it doesn't sound like a bad contact or overheating, but rather an internal problem in some semiconductor perhaps...?

This happens seldom enough to not be a big nuisance, but I would spend some time trying to fix it if I had the faintest idea of where to start. Oh yes, this is always when listening to the radio, I don't have any other sources connected.