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Kef 103 (help needed, component problem in one speaker)

 
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RenegadeUK
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Joined: 13 Aug 2004
Posts: 4

PostPosted: Thu Feb 02, 2012 2:55 pm    Post subject: Kef 103 (help needed, component problem in one speaker) Reply with quote

Hi this is my first post in the forum although i've been browsing the website for a few years now.

I've got a pair of KEF 103 speakers which were given to me about 12 years ago, and for some reason one of the speakers sounds a bit dull, compared to the other one which sounds fine.

Initially i thought one of the tweeters (SP1049) was faulty, although this morning i de-soldered both the tweeter and the main driver (SP1039) from both of the speakers, and ran them off the opposite circuitboards to test if they were faulty (or if the circuit/crossover was faulty).

Strangely enough the seemingly faulty tweeter/speaker sounded fine when i ran it from the circuit of the other working speaker, and so i now believe there to be a fault with one of the circuits/crossovers.

I'm averagely skilled with electronics, although i do have a multi-meter and i've been testing/comparing each of the components on the faulty circuitboard with the other working circuitboard, and have noticed a few differences between them both.

I just wondered if anyone could offer me any help in perhaps identifying which faulty component may need to be replaced. I absolutely love the speakers and they were given to me by a good friend many years ago and so they hold great sentimental value.

I'd love to try and get the faulty circuit board fixed, either by replacing a component etc. or by any other means.

Any help would be appreciated.

Here is a link to the KEF 103 speakers which i own.
http://www.hifiloudspeakers.info/Anatomy/SpeakerSystems/103/103.html


Many thanks

Guy (Cardiff, UK)
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ColinR
Über Contributor 1000+


Joined: 31 Jul 2004
Posts: 1175
Location: Staffordshire

PostPosted: Thu Feb 02, 2012 3:10 pm    Post subject: Reply with quote

Sounds dull, like there's more resistance in the circuit than there should be.

So it'll be either C2 2.2uF or C3 5uF.

Get a lead with two crocodile clips and "jump" C2 and C3, whilst playing a low level source to identify.

I'd suggest you replace all 8 capacitors in a stepwise fashion one speaker at a time until you find audio Nivarna or some other pop band Very Happy .

Jerry at Falcon www.falconacoustics.co.uk or the boys at Wilmslow Audio should be able to help you out.
If you're good at bits then RS, Farnell, Cricklewood, etc.
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Last edited by ColinR on Fri Feb 03, 2012 11:44 am; edited 1 time in total
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RenegadeUK
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Joined: 13 Aug 2004
Posts: 4

PostPosted: Thu Feb 02, 2012 9:50 pm    Post subject: Reply with quote

Thanks Colin, i really appreciate your help.

I'll definitely give the capacitors a test tomorrow and hopefully it will help me isolate the problem.

Thank you also for the link to the Falcon Acoustics website, it looks a great website and i'll definitely contact them soon. It would be great to get both of the speakers working properly again.

Many thanks again for your help, i'm hugely grateful and i'll definitely post another message here when i've hopefully fixed the speaker.

Guy (Cardiff, UK)
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RenegadeUK
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Joined: 13 Aug 2004
Posts: 4

PostPosted: Tue Feb 07, 2012 5:48 pm    Post subject: Reply with quote

Update:

Good news! I've since replaced all 8 of the capacitors (4 in each speaker), with new ones purchased from FalconAcoustics and i'm glad to say that both speakers are now working perfectly! Very Happy

I spent this morning removing and then replacing each capacitor one at a time, and have now spent the past couple of hours enjoying the improved sound quality. Both speakers now seem perfectly balanced and i'm hugely grateful for the help given to me earlier.

I had spent years thinking the tweeter had blown, although luckily i decided to test the tweeter and main driver last week by powering it off the opposite speaker circuit board, which proved that there was a fault in the circuit (thankfully not the tweeter).

Once again huge thanks to Colin for the help provided earlier. I'm so grateful to finally have the speakers working correctly. Smile
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rx7rotary
Intermediate Contributor 50+


Joined: 20 Feb 2012
Posts: 59

PostPosted: Thu Mar 15, 2012 8:14 pm    Post subject: Reply with quote

RenegadeUK wrote:
Update:

Good news! I've since replaced all 8 of the capacitors (4 in each speaker), with new ones purchased from FalconAcoustics and i'm glad to say that both speakers are now working perfectly! Very Happy

I spent this morning removing and then replacing each capacitor one at a time, and have now spent the past couple of hours enjoying the improved sound quality. Both speakers now seem perfectly balanced and i'm hugely grateful for the help given to me earlier.

I had spent years thinking the tweeter had blown, although luckily i decided to test the tweeter and main driver last week by powering it off the opposite speaker circuit board, which proved that there was a fault in the circuit (thankfully not the tweeter).

Once again huge thanks to Colin for the help provided earlier. I'm so grateful to finally have the speakers working correctly. Smile


Lovely to see such a great ending story ! Fantastic speakers enjoy them Smile)
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