How to repair Sonab OA12L ? (refoam+spider)

[sarkophage]

Hello everybody

I'm french, and I don't speak english very well.
I will try to repair 2 old speakers sonab OA12L, but I'm newbie and I don't know how.

This is my problem:





The name of this thing is "foam rot" isn't it ?
I don't know if I have buy a specific model/ref/serial number of foam, or if I can buy a standard one ?
I never open the speaker, is there something to know important before open it ? because I don't want to make a mistake.

I will follow this tutorial. http://www.haut-parleur.net/reparation.htm
It is in french but can you tell me if the technic is good with the pictures ?

Thanks for your help

[bohrok]

Refoaming Sonab woofers is not too difficult. However you should check that the spider is ok. The first SC165 woofers with horseshoe alnico magnets typically have weak spiders. Remove your woofer and look at the wavy spiral-like structure under the cone. It should be straight (i.e no sagging under cone). If the spider is not ok then refoaming does not help.

I have successfully used these surrounds:
http://cgi.ebay.de/2x-Schaumstoff-Foam- ... 53de773d77

Your manual is ok, but I would not recommend cutting the dust cap.
Here is a good manual in english.
http://www.audiofriends.nl/pdf/refoaming.pdf

regards
Martti

[sarkophage]

Thanks for your help martti, very usefull.

As you can see on this picture, the spider is very down:






I pull up the cone, should it be like this ? at the same level ?

[bohrok]

The cone rim should be bit lower than the frame. As stated in the manuals first glue the new surround to the cone. Then when glueing the surround to the frame you can try to pull up the cone slightly.

regards
Martti

[sarkophage]

OK, I will try to do that.
I will come back to post the result.

[sarkophage]

Unfortunately Audiofriends on Ebay doesn't send to France.
So I ordered this on a USA website: http://www.speakerworks.com/6_1_2_inch_ ... /swk65.htm

Finally, I unglue the dustcap. Because I have to pull up the cone and it was easier to center it by this method.





First test tomorrow...

[sarkophage]

OK, that's good

Thanks for your help Martti.

Now, there is work to be done:

[sarkophage]

Bad surprise

The spider of two speakers are dead, difficult to pull up the cone and the voice coil don't move freely.
I have to change them

I found this website: http://www.speakerbits.com/Default.aspx ... e=165&pi=1
But it is in Australia, shipping cost 15€...

Do you know a shop in Europe ?

[STDI!]

Bad surprise

The spider of two speakers are dead, difficult to pull up the cone and the voice coil don't move freely.
I have to change them

I found this website: http://www.speakerbits.com/Default.aspx ... e=165&pi=1
But it is in Australia, shipping cost 15€...

Do you know a shop in Europe ?

"the voice coil don't move freely" you say. Do you really think replacing the spider will make the voice coils move freely?
Do you know that you can buy new elements, developt by CarlssonPlanet (SCC) as replacement to the original? Just plug and play. http://www.hifikit.se/show_prod.asp?id=947.
Even if the site is in Swedish they write that they also send abroad. If this is interesting and you need help with translation just post your questions here. I'm sure you'll get help.

[sarkophage]

I think the problem is due to the spider, because it is totally deformed.
I hope changing spider will solve the problem, if it doesn't, I will buy new subwoofer. But I will try to repair before put them in the dustbin.