Depending on which version (left or right) doesn’t work, you should check the traces on the boards. 
Components are affected. Before replacing them you should clean the surface with a fiberglass stick. You will find several broken traces which you won’t see with your eyes when are still covered by pieces of old foam. 
Even around some testpoints there are possible broken traces to be found. All can cause the above described symptoms. 
Start at the places where you found the foam sticked at the board.  

Hi Beobuddy

Thank you, it all has been cleaned and traces were repaired under a microscope and tested (my eyes are too old to work without it, and as I also repair cellular phones it is not possible to solder without a microscope. Most repairs are iphones and it is always the same problems, like you guys know better than me with B&O, that is why I ask here ;)

But dit not check around testing point good idea will check tonight.

Hi everyone.

I had already replaced R96 but taking voltage again found 29 volts but nothing on the other side.

Could it be that a wrong value ont the parts around it that had the wrong value could have blow the resistor ???

Who knows !!!! anyway it's finaly working, now I just have to order new parts like resistor, transistor, caps etc that I pulled out of a working unit

I alsays use the parts of a working unit because exchanging from one place to another same place is very easy and you know it is working.

Thanks to all for the help and yes that FOAM ROT is a plague that makes us works hours to clean and rebuild the traces, for me this is a problem that was there the day that they have been purchased so B&O should have been responsable for it and recall or sending new foam free at least.

I have a 2008 chrysler grand voyager and the emblem on the stering wheel is hurting when the airbag deploys in an accident.

Well chrysler sent me a letter that they are recalling all the cars even that I am not the first original owner of the car. But today they have acces to our address through our VIN number.

Keep this forum repair up and working as this is good for the earth and saving our kids future house.

OUPS... Talked a little too fast, the top speaker is not working but I should managed... The tweeter is dead.

When you change tweter or boomer there is a procedure in the service manual to adjust like the number on the back of the speaker.

Their is plenty of number on the back, which number ?

Congratz on your successful fix of the original problem!

chti59 wrote:

.

Their is plenty of number on the back, which number ?

I just googled the net and it seems that some replacement tweeters do show the db-level on their label while others do not. Here's one example with -0.2dB:

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If you don't have that, you're out of luck. All you can do is to assume that it has a flat frequency response and adjust 2R51 as if the chassis were 0.0dB.

Alternatively you could measure the actual frequency response of the speakers, but that needs a measuring mike and some high quality - thus high price - equipment and that's probably not worth it.

Are both tweeters without dB-value, I mean the damaged one and the replacement tweeter? Even the full range speakers? If so, maybe B&O dropped the concept of measuring and adjusting the response due to cost reasons!? Who knows...!
In this case it's probably best to set the amplifier to middle position, i.e. 0.0dB.

Hi Manfy

I do not have a replacement, this night I pulled out the treble and open it, the 2 wires were not connected to their little pole, how can that happen I do not know. I have Tried to solder the wire back on their place but the solder is not staying on it, it is running aways and the wire were too short.

Then I have opened the tweeter just to see if inside there is still a continuity to the wire and yes the wire is OK but was too short and impossible to solder.

I will effectively put a new one and as you say put the adjustable resistor in the middle position.

Here is the pictures of mine opened.

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Interesting!

I'd say it's unlikely that the voice coil wire broke because of overload. If so, that would have happened somewhere within the coil.
Probably the previous owner was "playing around" and accidentally broke those wires.

Yes, you cannot easily solder them. Similar to transformer wire it is lacquer coated and it can withstand temperatures up to 200+ Celsius.
On thick wire the lacqer needs to be scratched off for soldering, but don't do that here! It could damage the voice coil beyond repair.
Set your soldering iron to max. temperature (which is usually around 400C) and carefully "burn off" that insulation at the last 5mm where you want ot solder the connecting wire. Once that's done, you can solder it easily to a copper strand for connection to the terminal.

Do NOT readjust the amp setting yet if you are using the very same speaker! If it is the original driver, you can assume that the setting is correct.
Fix the wires and test the speaker. If it sounds good (and balanced with the other channel) leave the amplifier setting as is!

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PS: An afterthought: You could also use a normal cigarette lighter to burn off the insulation at the end of the voice coil wire! The Butane flame surely burns beyond 1000C and that will definitely burn off any lacquer coating...and it is non-contact, i.e. no danger to the wire because of mechanical forces!

Hi

Just checked and the other speaker tweeter is also dead, so certainly to much volume.

Which glue are you guys unsing to reglue the dome of the tweter.?

chti59 wrote:

Hi

Just checked and the other speaker tweeter is also dead, so certainly to much volume.

Hmmmm, I think you're jumping to conclusions -- in this case a potentially wrong one!

It can't be an excursion fault because tweeter coils don't travel that far. It can't be overheating because you would see a fried voice coil or at least signs of overheating. The connecting wire definitely wouldn't fail of overheating -- mechanical stress and aging of the wire maybe, but certainly not overheating.

Additionally, I see in diagram B that the Beo designers added a 'treble protect' circuit to the amplifier. If I read the diagram correctly, it shorts the input to GND if there is an excessive output voltage. That means the tweeter is basically overload protected.

Now I'd actually be more worried that something might be wrong with the amplifier chip or this overload protection circuit.
I guess it's time to measure the output voltage as per service manual: connect a signal generator with a 10kHz, 100mVrms signal and check what you get at the tweeter output. If you measure the input pin1 of the STK4152, you can assess the load level of the chip and the speaker. The STK4152 datasheet shows that an input of 100mV is roughly equivalent to 10W at 40dB gain; 200mV is above 40W, ie. actually beyond the spec'd 30W max output.

If you don't want to check that, you're running the risk of damaging new tweeters quite quickly!