Help with speaker recap

[fdejong]

So I bought some mid 80's B&W speakers the other day and it turns out the tweeter wasn't working at all. Thought I found the answer when I opened it and reconnected the black wire.

But, still no go. Opened it up again and noticed one of the capacitors looked bad. I cut the parts out and it has white residue all over it, also it looks like it melted the plastic underneath it!

So, looks like I need to replace them, but I have no idea where to start...

-Where do I find replacement capacitors?
-Can I resolder them myself? I have never soldered before, but am willing to learn.

The markings on the capacitors are:

Large blue cap:

ALCAP 10MFD 70VNP +-10% LL BW
93-8435

Small blue cap:
ALCAP ????? ????? +-5% LL BW

Square white thing:
5w 2.2 Ohm symbol? J Expotus

Can anyone identify the parts I need to buy and where to buy them?

And other advice is welcome to this newbie too

Thanks

Frank

[Sir.Byrd]

Partsexpress is good,
Dayton 1% poly caps are very good for the price.

[Sir.Byrd]

http://www.parts-express.com/pe/psho...Number=027-244
To me it looks like two 10 MFD caps paralleled to 20 MFD, and a single ? MFD cap.
So you could either mimic this again or get one ? MFD cap, and one 20 MFD cap.
Try scrapping off the goop to read it better.
Put these in series to get 2.2 ohms.
http://www.parts-express.com/pe/show...number=005-1.2
http://www.parts-express.com/pe/show...rtnumber=005-1

[fdejong]

Thanks Sir Byrd! Although I'm not sure yet how you are correlating the 'MFD' with the parts you linked.

It looks like of the two together, one is 10 MFD and the other 8 MFD.

The one still in the box is 7 MFD.

To keep things on a budget, can I reuse the 2.2 ohm white part, or is that asking for trouble?

I labelled the picture here:

[Sir.Byrd]

Originally Posted by fdejong

Thanks Sir Byrd! Although I'm not sure yet how you are correlating the 'MFD' with the parts you linked.

It looks like of the two together, one is 10 MFD and the other 8 MFD.

The one still in the box is 7 MFD.

To keep things on a budget, can I reuse the 2.2 ohm white part, or is that asking for trouble?

I labelled the picture here:

Since the 2.2 ohm 5W resistor was in the trouble zone, I would just replace it. The issue looks like it was caused by the resistor getting too hot.
If you want to, you can replace the 2.2 ohm resistor with a single Mills 2 ohm resistor, rather than 2 resistors to get an exact value, I didn't know how anal you are about getting things perfect (I am)

Okay, so order two of these http://www.parts-express.com/pe/psho...Number=027-242
two of these
http://www.parts-express.com/pe/psho...Number=027-238
and two of these
http://www.parts-express.com/pe/psho...Number=027-244
and two of these
http://www.parts-express.com/pe/show...rtnumber=005-2

This all ends up to be kind of pricey so if you want to you can use a single 20 MFD (uF=MFD) cap in place of the 8 and the 10 since that would only be a 10% change...

good luck!

[tubed]

I've noticed alot people jumping to the conclusion that they need to replace the capacitors on their speakers because of no sound coming from a driver, many times without removing the driver to test for sound..... In this case couldn't the "melted plastic" under the suppossed offending capacitor simply be hot glue? After all " it turns out the tweeter wasnt working at all"".?????

[Sir.Byrd]

Before you order anything, try checking the tweeter at its terminals with a digital multimeter set to ohms to see if it reads open. If it reads open you a screwed.

[fdejong]

I hadn't thought of that.

And unfortunately, lacking a multimeter, I couldn't do as Byrd suggested.

So, I put them volume on my Beomaster 1900 very low and connected the speaker leads directly to the tweeter (probably a huge no-no, but I decided to risk it).

And, luckily for me, they still work great.

So, next step is to order myself those caps that Byrd suggested and a soldering iron and make a project out of it. I'm seriously getting into this hobby and am really looking forward to it.

Still haven't decided whether I'm going to stay completely perfect, or if I'll go with the 2ohm unit and the 20MFD cap. If I wasn't unemployed at the moment, it would be an easy choice.

Are electrolyte caps a really bad option?

[OverLoad]

The easiest first step is to eliminate the tweeter as the problem. If you can't DCR check with a meter than swap the tweeter from the problem speaker into the working speaker. You can try it directly to the amp output at very low volume (it will be getting full frequency range) but for the 2 minutes it takes to pop them in and out why not be safe and hook it up properly If the tweeter is not the problem then check the wiring which it seems you have and THEN on to the crossover.

The 5W resistor nestled right in between the 10 and 8uF caps is the melting source no doubt and is not a great idea. Even if it turns out the crossover is NOT the problem, I would probably rework them anyways. Replace the BPE caps with some metalized polypropylene or at least polyester. Staying on budget as you say, you could use a single 18uF polyester (just about anything will be better than the BPE's) also eliminating the need for the parallelled 10 and 8uF. You will need to change up the mounting since the polypro or polyester will no doubt be larger physically and can then be placed away from the resistor too. Staying on the cheap you also don't need $4 mills. Replace the 5W wirewound with a 2.2ohm 10W wirewound for .30 cents.

[OverLoad]

fdejong, didn't refresh my page and missed that you had posted back in the meantime. Ok, so you did end up eliminating the tweeter. The BPE's are not necessarily a "really bad option" but for not a whole lot of extra scratch you can use something better or you can get exotic and pricey.

[fdejong]

Thanks for chiming in Overload.

"The 5W resistor nestled right in between the 10 and 8uF caps is the melting source no doubt and is not a great idea."

You know, that would explain the white residue on the caps, but otherwise not a sign of leaky caps.

So, now I'm thinking about getting (for both speakers):

2 x 18uF polyester
2 x 2.2ohm 10W wirewound
2 x 7uF polyester

I'll start searching around the parts places, but any help would be much appreciated

[ryuuoh]

That white stuff looks like cyanoacrylate glue blooming.

[Sir.Byrd]

Originally Posted by fdejong

I'll start searching around the parts places, but any help would be much appreciated

my help not good 'nuff?

[Face]

Mr. Byrd is dead on, I'd follow his advice.

[MarkAnderson]

Originally Posted by fdejong

Are electrolyte caps a really bad option?

Not at all. They were obviously good enough for B&W.

If you want to retain the original character of the speakers, they might well be the only option. I would suggest a good audio-grade Dayton/Bennic or such.