Re: Beomaster 1900 does not come out of standby anymore

HarryPierce — Sat, 28 May 2011 23:45:29 GMT

And here the conclusion: It turned out that 2TR22 (the transistor sensing the "stand-by" button) had a burnt through B-E junction. This apparently resulted in a permanent stand-by request, competing with turn-on requests from the other buttons.

Beomaster 1900 does not come out of standby anymore

HarryPierce — Sat, 28 May 2011 22:40:56 GMT

Hi Vintage Community:

After a recent re-capping and re-lamping my BM 1900 worked very happily for some time. Now, out of a sudden, it started the following strange behavior: When touching one of the program buttons to wake it up from stand-by, all that happens is that the relay starts clicking in ~150ms intervals and the lights briefly light up in sync with the clicking (while the standby LED goes off in sync) as long as I keep touching the button. I hooked up the oscilloscope to the power supply circuits, and it seems that all voltages are present (and constant) for about 20-30 ms and then everything shuts down. Then after about 150 ms it comes on again, and repeat (see screen shot below as measured at TP15 (the 15V supply)). I checked all the transistors in the supply and they seem to be o.k....IC9 is also o.k....it is almost as if somehow stand-by is initiated shortly after start-up, and then the next start-up is tried and so on...

Suggestions would be appreciated very much! Thanks much in advance!

Rudy

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Re: Beomaster 1900 does not come out of standby anymore

Beomaster 1900 does not come out of standby anymore