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Hi, Hoping to get some ideas on how to fix this S75. Neither the mid nor the tweeter work when I plug the speaker in. I've tested both drivers and the work.
I've taken a look at the crossover and nothing seems amiss. All the soldering looks solid.
Help, any ideas on how to fix. Thanks.
Welcome to Beoworld.
You may get more folks looking in on a question like this by asking in the Vintage forum. Posting in the North America section may have very helpful folks from Europe not even seeing your question.
Anyway, if the drivers are OK, then your capacitors in the crossover network have probably exceeded their useful lifespan. I have brought back a pair of S45-2s by replacing the crossover capacitors. I first thought it was a faulty midrange, but replacing the midrange wasn't the answer. Once I replaced the capacitors, the speakers came back to life and the original midrange driver (actually, the "phase link") turned out to be still functioning properly.
Electrolytic capacitors have a fluid in them (an "electrolyte," thus "electrolytic" capacitor) which will dry out over time. Eventually this leads to poor sound and ultimately complete failure (open circuit).
Replacement capacitors can be found many places. I have got them from member "Dillen" on this site, and from Meniscus in Michigan. Assuming you're in the continental US, if you order from Mark at Meniscus on Monday and choose USPS priority shipping for about $10, you could have replacement capacitors on Wednesday.
Thanks for all of the info. I'll try doing both!
I haven't repaired a crossover before, so...
Is it as simple as getting the #s off the existing caps, buying new ones, removing and soldering in place the new?
Thanks.
Yes! I have the cross over diagram for you.
Peter
Thank you!
Bummer, I can't read it. Too small.
Click on it and then zoom. Not a brilliant scan but legible!
SwingModern: I haven't repaired a crossover before, so... Is it as simple as getting the #s off the existing caps, buying new ones, removing and soldering in place the new? Thanks.
As Peter said, yes it can be that simple. When I refurbished a pair of similar M70s, I also replaced the resistors and rewired everything inside the box.
But I'd like to ask a question. Why are you fixing this pair of S75s? If you plan to keep them, by all means fix them. But if you're fixing them in order to sell them, I'm not sure I'd bother. "As is, untested because I don't have the right cables" B&O speakers sell for about the same amount of money as "fully tested and working and sound great."
The real key for selling a pair are appearance and having the original stands.
So - are these S75s for your own use?
Yes, I'm using them. Not planning on selling.
If you want to do the job yourself, the simplest way to do it is order the caps from Martin (Dillen on the forum) mail him, if you want to buy yourself wherever you are, be sure to buy bipolar caps, if you cant get the exact sizes (uF) you can parallel 2 caps to get the right size.
Before starting desoldering, make sure to mark cables and caps solder points, and while you are at it check the resistors as well. Before ordering anything check the driver voice coil on the drivers not working, and check if the cone is moving freely in and out.
Collecting Vintage B&O is not a hobby, its a lifestyle.
I suggest you check the tweeters and midranges for continuity BEFORE you start work on the crossovers.
Martin
SwingModern: Yes, I'm using them. Not planning on selling.
Outstanding.
We like pictures. You can see what I did with my M70s here.
Here are mine.
Mark at Meniscus also sells grill (or "fret," as most people on this forum say) cloth in at least 5 colors.
Rich: Mark at Meniscus also sells grill (or "fret," as most people on this forum say) cloth in at least 5 colors.
But if you want the Rich FS hurricane fabric you will have to ask Rich´s wife, Meniscus wont have this very special fabric.
Sand and oil your very nice looking speakers, put on new fabric, do the crossovers and the drivers (if necessary), and you have speakers for the next 20 years.