Shortcit in motor board Beosound 9000 Type 2561 Sw2.1

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alanso Posted: Tue, Oct 27 2015 1:19 PM

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beosound-pcb35.jpg

Hello B&O lovers,

First I want to thank you for reading about my problem, very appreciated

I have a big problem with my Beosound 9000 Type 2561 Sw2.1 .

I didn't used the cd-player for years and after moving I want it to use again.

But it seemed the laser was not reading  the cd discs anymore.

I ordered a new laser and installed it and after that  it played cd's like it was a new one

But one day later when I turned on the cd-player it didn't respond at all.

No display and no led light, totally dead.

Strange because nothing happened between the time it worked and stopped working.

I searched for the problem and found out there was a shortcut in the motor control board, pcb35.

At the moment I disconnect the motor board the red LED light start burning again.

I found on the motor board two broken transistors TR18 and TR19 both BUZ71A

But when I replaced the transistors and turn the power up right away TR18 blows up.

When I took out TR18 the shortcut was gone and the red light was burning again.

Even when I disconnect all cables from the motor board except connector 51 the shortcut is still there.

I noticed there is a high current flowing on pin2 from connector P51 when TR18 is soldered back in the board

I could not find any broken components on the motor board and now I do not know anymore where to look  for.

I'm also not sure if I use the right service manual because I only could find one from MKIII but it looks similar

In the attachments you see TR18 and the connector P51 with the high current om pin 2.

Any advice would be very welcome

regards Alan Sodenkamp