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Kef 104/2 restauration advice needed from Australia

 
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andreasb



Joined: 14 Jun 2012
Posts: 5
Location: Sydney , Australia

PostPosted: Fri Jun 15, 2012 5:43 am    Post subject: Kef 104/2 restauration advice needed from Australia Reply with quote

Hi 

Through reading the internet i found your website. 
I am someone that loves music and fell in love with good sound , so I recently purchased 
a pair of Kef 104/2 early versions (nonbiAmp).  The speaker serial numbers are 014139A and 014139B.
They were going to be trashed and sold in pieces  by the former owner.
I can't afford thousands of dollars for this passion
but I loved the Kef's and really wanted to get a pair , they don't ver often come up for sale over here .

So my  Kefs need refurbishment .
I had in mind  to give it to a speaker repair shop.
Unfortunately I haven't found one that really wants to touch them here isn Sydney/Australia . Not the time and expertise 
Alternately I am willing  to learn how to do it myself
 I thought that was going to be an easyish job . I refurbished some Bose 601 s2 before , speaker refoaming , not too hard .

Now I'm kind of forced to do the restoration myself at least take parts out for repair or exchange.
I'm learning it is a job where I need some expert advice as I want to do it right.
I'm looking information how to get started .
There is information out on the internet, but not enough and specific to get started
I'm not too shy to get the screwdriver out , I am cluey and like learning.

I haven't started the project 




Main question about my Mid range 
The lower midrange cone B110 is damaged   in speaker 014139A., is not working well
The sound coming from the damaged midrange cone is a little bit retractable and blurry at any volume level whilst playing music when compared with a normal functioning midrange cone.

Need  test if it is the crossover or driver by swapping them across

If it is the driver :
Can it be repaired or even exchanged with original or replacement?
Are there instructions somewhere on how to take it out ( read driver   glued to the plastic box )
Who would you recommend for repair or is there an alternative speaker replacement?

If it is the Crossover :
Have read on the internet that it is not necessarily easy to get to it
Are there instructions how to open it from the bottom.  The  lid is screwed but also  glued .
Can I just exchange the capacitors with the right values for new ones or is that to simplistic?
Who would  the best source?
Or should I only can send it away ( not an electronic expert , but can solder)


I am live Australia but happy to send them away.


Tweeter:
sounds a bit faded.
Would you recomment to  exchange tweeters due to age? 
 If yes which ones ? replacement or original kef?
What is involved to change them to third party( adjustment of Crossover and/or tweeter only) ?

Bass driver:
Bass driver needs refoaming, middle donut , possibly surrounds.
Have done that before with the Bose speakers.
Looks the most straight forward . Anything to keep in mind for this  job on these speakers?


I know a lot of questions , but I really want to get these speaker going again and restore the former beauty .
I would be very thankful for an answer as I want to get started  as soon as possible

thanks 
Andreas
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ColinR



Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Fri Jun 15, 2012 2:04 pm    Post subject: Reply with quote

Quote:
Main question about my Mid range
The lower midrange cone B110 is damaged in speaker 014139A., is not working well & Can it be repaired or even exchanged with original or replacement? & is there an alternative speaker replacement?


Your speakers are toast Crying or Very sad .

Any mechanical or electrical damage to the midrange is unrepairable due to the chassis less design, you won't be able to remove the surround or spider without causing further damage due to the glues/materials used.

Chassis less: the magnet is glued to the rear of the mdf enclosure, the fabric spider and roll surround are fitted into precision routings on the front.

Not repairable by professionals unless you are a lotto winner and it doesn't have exchange drive units despite what sleezeBay sellers (who strangely don't offer crossover redesign services as part of their price Evil or Very Mad), would have you believe.

KEF in the UK used to be able (a long, long, long time ago) to swap out the midranges, BUT cleaning the bogs after curry night with a toothbrush was apparently preferable Sad .

For DIY, single replacement KEF SP1274 units were ~£120 in 2006, so you could ask them very, very nicely if there was still one on a shelf somewhere.


Quote:
If it is the Crossover


No, the midranges are in parallel to make a 4 ohm load, so it's either not bad or all bad.

Quote:
The lid is screwed but also glued


The lid should be bolted and held by an automotive mastic which can be softened with a hair dryer.

If the bass is glued, you won't be able to gain access to the lower bass unit and your speakers are toast Crying or Very sad .

Quote:
Tweeter: & Bass driver:


Quite irrelevant until you sort out whether you can “fix” your midrange unit.
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This post or any other information supplied to this website or any other by myself is not available for any form of commercial purpose i.e. to hi-fi magazines or as sales and marketing material for sleezeBay or Audiodogging pimps and the like.
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andreasb



Joined: 14 Jun 2012
Posts: 5
Location: Sydney , Australia

PostPosted: Fri Jun 15, 2012 8:17 pm    Post subject: All bad? Reply with quote

Quote:


No, the midranges are in parallel to make a 4 ohm load, so it's either not bad or all bad.


Tell me if i understand correctly?
The crossover is not feeding it so it can't be crossover.
So it means mids are not working properly because they are most likely fried .
Sorry just making sure I understand, pretty new to the whole subject.
I guess the answer I was fearing.
So no hope unless I find someone who can sell me the whole assembly.
Any tips for a lead where to start looking
Just not wanting to give up and junk the speakers
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speakerguru



Joined: 18 Nov 2005
Posts: 737
Location: Green Hut, Tovil

PostPosted: Sat Jun 16, 2012 8:59 am    Post subject: Reply with quote

What Colin is saying is that the two midrage units are in parallel so they are both getting the same signal from the XOver. If one sounds OK then most likely, there is nothing wrong with the XO.

How badly damaged is the midrange? Is just the cone split or are there missing bits? Could it be patched up? I doubt that any repair specialist could get replacement cone/coil assemblies for such an old model.

BTW love the spelling of restoration in the post title - is it from a speaker "cookbook" Laughing ?
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andreasb



Joined: 14 Jun 2012
Posts: 5
Location: Sydney , Australia

PostPosted: Sat Jun 16, 2012 10:17 am    Post subject: Reply with quote

Had to get you guys smiling somehow:)
Thanks for any help, will keep you posted with further developments.
In case someone has a working midrange assembly
flying around please post here. Or even a lead to a classic speaker part dealer
Would really make someone happy .
Thanks
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andreasb



Joined: 14 Jun 2012
Posts: 5
Location: Sydney , Australia

PostPosted: Sat Jun 16, 2012 11:04 am    Post subject: Reply with quote

The damaged mid driver looks fine no physical damage to the outside .
The sound coming from the damaged midrange cone is a little bit retractable and blurry at any volume level whilst playing music when compared with a normal functioning midrange cone.
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speakerguru



Joined: 18 Nov 2005
Posts: 737
Location: Green Hut, Tovil

PostPosted: Sat Jun 16, 2012 12:15 pm    Post subject: Reply with quote

andreasb wrote:
The damaged mid driver looks fine no physical damage to the outside .

.................Question How is it damaged then Shocked ?
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andreasb



Joined: 14 Jun 2012
Posts: 5
Location: Sydney , Australia

PostPosted: Sat Jun 16, 2012 1:08 pm    Post subject: Reply with quote

as i described earlier it's not performing properly, I guess it's internally, not too sure, maybe coil. That's why I am posting.
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speakerguru



Joined: 18 Nov 2005
Posts: 737
Location: Green Hut, Tovil

PostPosted: Sat Jun 16, 2012 2:38 pm    Post subject: Reply with quote

The description in the OP is vague. Disconnect the amplifier. Does the cone move freely in and out if you push it gently? Are there any scratchy noises as you move it?
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