Hi,

the voltage should be something around 110V AC.

Sorry, there is absolutly no circuit plan for these boards available... at least i have never seen something like that, just the normal service manual, which contains no circuit description.

The only thing i can say: replace all transistors on this cooler.

You have checked the coil and the signals with an oszilloscope? If one halfwave is missing, the voltage on the output is decreasing to 30-50V... exactly what you found.

Martin

you can perhaps take a high quality top/bottom pictures of the board to help us to make a back engineering of the schematic :)

maybe this will help...

Thanks for the posts - I've got a bit of lead time for the NPN transistors to turn up, but this is all great supporting info.. I'm on the right track hopefully - I'll update how it goes

Hi, did you ever get this working ?

Im having a totally dead voltage(0) on black/brown wires, and I cannot hear any humming from the coil at all, otherwise the remote is working perfektly, just like yours :)

I have checked the 1A250v fuse, and it is fine..

Any great ideas ?

Hi,

Sorry to report that I have not had much good luck with this unfortunately - as well as new NPN and PNP transistors, I tried a whole replacement PCB1 board, and it still made no difference.

The fault finding flowchart in the manual recommended both PCB 1 and 2 be replaced for this issue, and I decided to cut my losses where they are and just sourced a fully functional BL7000 - even with the backlight inoperative it's OK as a #2 unit handy elsewhere in the room to adjust volume etc.

There must be a switching function driven by PCB2, but I'm even less sure where to start with that.

Hi, thanks for your reply, that actually helped me a lot, I have the Service Manual, but did not think that it could be from PCB2/3 the control of the trafo could be located :)

In my case this makes a lot of sence, since I measure 0V at the trafo, so the circuit is not even powering up... I have exchanged PCB2 in my 2 BL7000's, and both processor boards are actually working in my "working BL7000", so the fault could be on PCB3 or 4 also, don't know if the display board is exchanging data with the processor board, and should return "ok" for the processorboard to turn on the backlight..

But, I have a friend at B&O and he has the BL7000 now, he will try to do some measurements on it and see if he can do something :)

I will let you know..

/Weebyx

And..... My friend has just gotten back to me, he has changed TR37 / C15... and now it works like a charm again :)

/Weebyx

One more thing ...

Have you tried changing the backup battery on PCB2(processor board) ? Sometimes a low voltage there, can cause side effects..

/Weebyx