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Beolab 4000 questions - foam rot

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h1npw
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h1npw posted on Sun, Mar 5 2017 2:06 PM

I'm looking to buy a couple of pairs of these great speakers from flea bay... Can anyone tell me 

1) How can you differentiate between those with the black foam inside them that eventually turns to goo, and those with the "stable" white foam, without asking sellers to take their speaker to bits?

2) Did they change the foam when they started production of the Mk2?

3) Did the serial numbers continue in sequence from Mk1 to Mk2?

4) is there a specific serial number point when the foam changed?

Any info will be greatfully received!

Cheers

Nigel

 

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Michael
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Beobuddy:

Don't make it more than it is. There isn't a "gap". Just all BL4000 mk1 prior to serialnumber 15-16 have the same foam.

I have serial number serie 14... and they seem to be high quality and white. Tried pressing it and it was very much like a stiff sponge and not at all deteriorated.

Looked around with a flash light and could only see a lot of white damping material inside. No black what so ever.

I don't think these have been modified and they sound really amazing. Now I feel good knowing they are fitted with the white material instead of the black. Smile

So I think maybe you were wrong. Smile

Beolab 50, Beolab 8000 x 2, Beolab 4000 x 2, 
BeoSound Core, BeoSound 9000, BeoSound Century, 
BeoLit 15, BeoPlay A1, BeoPlay P2, BeoPlay H9 3rd Gen, BeoPlay H6, EarSet 3i, 
BeoVision Eclipse Gen 2 55", BeoPlay V1-40, 
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marexy
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Thnaks

getting closer to :)

I have a par of SN: 142....and with black foam..

so ..maybe somewere from 142..til 147... they change from black to white..

 

 

Michael
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marexy:

Thnaks

getting closer to :)

I have a par of SN: 142....and with black foam..

so ..maybe somewere from 142..til 147... they change from black to white..

Mine is 14335xxxSmile so Pretty close

Beolab 50, Beolab 8000 x 2, Beolab 4000 x 2, 
BeoSound Core, BeoSound 9000, BeoSound Century, 
BeoLit 15, BeoPlay A1, BeoPlay P2, BeoPlay H9 3rd Gen, BeoPlay H6, EarSet 3i, 
BeoVision Eclipse Gen 2 55", BeoPlay V1-40, 
BeoCom 6000 and so much else :)  

h1npw
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h1npw replied on Tue, Mar 7 2017 10:37 PM

Wow! That's amazingly! Isn't the internet great!?

So we know it's somewhere between 142... And 143335.  Marexy - can you give us a 5 digit start to your serial number?

Any more volunteers to do a "Michael" and have a look so we can narrow the gap even more?

Cheers

Nigel

StKong
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StKong replied on Tue, Mar 7 2017 10:50 PM
I happily volunteer.

None of my screwdrivers and bits will unscrew, though, so does anyone have a specification for screw sizes?

I have 2 sets at hand, both from 1997. One is 14069xxx and the other 14553xxx. The moment I get them taken apart, I will let you know.

h1npw
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h1npw replied on Tue, Mar 7 2017 10:57 PM

Don't know the exact size, but it's a small torx type screw head 

If our Sherlock Holmes work is correct you 140s should be black and your 145s should be white.

Make sure you let us know!

Cheers

Nigel

StKong
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StKong replied on Tue, Mar 7 2017 11:08 PM
h1npw:

Don't know the exact size, but it's a small torx type screw head

If our Sherlock Holmes work is correct you 140s should be black and your 145s should be white.

Make sure you let us know!

Exactly! I hope the theory holds water and that I can confirm the above to be the case. The collective wisdom of the internet is a wonderful thing.

I'll be back with more ;-)
marexy
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I'm disappointed in some forum members who refuse to share experiences and advice. ...yes yes ..upgrade to silver and gold .. :(

Torx 8 is correct one.

But I have a hunch that they were BL4000 manufactured in 2 or 3 different plants and not only in one factory line.
According to the labels, print, indications ..

..for me....Best sounding , versatile used B&O speakers ever !!...for the money of a new sneakers!
some photo of black foam...bljak..
StKong
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marexy:

I'm disappointed in some forum members who refuse to share experiences and advice . ... yes yes ..upgrade to silver and gold .. :(

Torx 8 is correct one.

But I have a hunch that they were BL4000 manufactured in 2 or 3 different plants and not only in one factory line. According to the labels, print, indications ..

..for me....Best sounding , versatile used B &O speakers ever !!... for the money of a new sneakers! some photo of black foam...bljak..

Thanks, marexy, your foam looks more stable than I thought it would.

What is your assessment?

Regarding disappointment, I wonder if users truly abstain from answering based on others' membership status. That would be sad.

I am wondering if that is why nobody replied to my question about where to acquire original grade white replacement foam.

Either way, I appreciate the collective wisdom of the forum, and the huge work by the good people behind it.

I am curious what lies behind the silver and golden doors, so I will see for myself now ;-)
marexy
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Hi

Pictures were takem before i start to remove foam. It's very very fragile and sticks on fingers or any other material if you touch to hard.

I did not replace foam with original. You can buy foam like original maybe some other colour and cut it.  works ..with no problem.

I did some sound test and it is no difference in sound !!

So no need to buy original  if it is more than 10€ per speaker.

You can repair broken spakers with 5€ costs if you are handy man :)

Maybe some one will be angry for let go of these information...but sorry ...why pay 250€ if you can DIY.

Yes our local service want 250€ for job...OMG..why .. it's 1 hour time job if you DIY.

And some additional info...BL4000 are way way better than BL4 ...with all my tests i made :)

I know what i'm talking about ..

 

 

 

 

 

Beobuddy
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marexy:

Torx 8 is correct one.

Torx 10 to be more precise. Torx 8 can damage the inside of a T10 screw when more force is used.

But for this occasional job T8 will do.

 

Beobuddy
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marexy:

You can repair broken spakers with 5€ costs if you are handy man :)

Maybe some one will be angry for let go of these information...but sorry ...why pay 250€ if you can DIY.

Yes our local service want 250€ for job...OMG..why .. it's 1 hour time job if you DIY.

 

 

Stop putting the dealer into a dark light.

The dealer won't charge you  € 250,- for just cleaning.

Often these speakers are brought in when they already have weird symptoms or already are not working.

On a rare occasion customers bring in the BL4000 before the malfunctioning.

As your pictures show you can see that the foam lies accros the PCB layer. More than one culprit probably could have caused a broken BL4000, or are about to break. the places of foam changes wheter it is a left or a right version.

As you've mentioned that you fixed several, you should or could have known that. One might be lucky.

Most often a broken BL4000 isn't fixed by just cleaning. (And I've done a 100+ of these, believe me). And SMD soldering skills are beyond most of the majority here. Let aside the equipment you need for proper soldering.

One can attemp to remove and see what happens, but isn't a quarantee for succes, as you say.

 

StKong
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StKong replied on Wed, Mar 8 2017 10:19 AM
Beobuddy:

Stop putting the dealer into a dark light.

The dealer won't charge you € 250,- for just cleaning.

Often these speakers are brought in when they already have weird symptoms or already are not working.

On a rare occasion customers bring in the BL4000 before the malfunctioning.

As your pictures show you can see that the foam lies accros the PCB layer. More than one culprit probably could have caused a broken BL4000, or are about to break. the places of foam changes wheter it is a left or a right version.

As you've mentioned that you fixed several, you should or could have known that. One might be lucky.

Most often a broken BL4000 isn't fixed by just cleaning. (And I've done a 100+ of these, believe me). And SMD soldering skills are beyond most of the majority here. Let aside the equipment you need for proper soldering.

One can attemp to remove and see what happens, but isn't a quarantee for succes, as you say.

I have asked around in the Copenhagen area, and it isn't easy to find somebody interested in undertaking the foam replacement. This may vary based on geography, but I am going to attempt a replacement as soon as I have assessed the extent of deterioration and found the proper replacement foam.

I would much rather leave this to a repair shop, but it seems they have better things to do.
Beobuddy
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marexy:

I did not replace foam with original. You can buy foam like original maybe some other colour and cut it.  works ..with no problem.

I did some sound test and it is no difference in sound !!

So no need to buy original  if it is more than 10€ per speaker.

 

The foam is partial used for acoustic purposes, but also for preventing damage to the wiring and unwanted possible vibrating noise of it against the housing/PCB/etc. These drivers do not have a casing of its own. So the entire interior is endured to what the drivers deliver.

If foam wasn't neccesary, B&O wouldn't have used it. If not, then the question might now be why the wires are perished (probably caused by the sharp soldered parts)

 

marexy
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marexy replied on Wed, Mar 8 2017 10:29 AM

I agree with you !

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