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Bringing some AR15EGs back to life


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Hi All. I’m a newbie to speaker restoration but have recently acquired a very cheap pair of AR15s that I’m looking to bring back to life.

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The woofers needed a refoam (which I have done since I took this picture), but sadly the tweeters are completely shot. I’ve tested them with a multimeter and nothing, completely flatlining. I’m in no great rush to get them up and running again, so while I play the (no doubt long) waiting game for a suitable donor with tweeters to turn up I thought I would have a bit of a tinker with the cabinets.

Cosmetically these are in really good shape, with just a slight bit of wear and tear and have cleaned up nicely. Both badges however need a touch up, and I wondered if anybody had painted theirs before and had any tips on suitable paint? I’m assuming really any good suitable matt black paint would work, but I thought I would check and see if anybody had any tips on what may work better than others?

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Although I’m unlikely to do much more to the speakers at this stage until I eventually find some working tweeters, when/if I finally do would it be recommended to also go down the route of a recap?

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Thanks in advance for all your help!

Richard

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Good Morning,

    Well the tweeters might be repairable, RoyC and Chris1 may chime in on that. Did you remove the tweeters from their circuit and test them, that would be my suggestion. The black and red caps should be replaced because of value drifting. As for the badges paint(dull black) is usually works well. Of course good luck and keep us posted.

RickB

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Thanks Rick. Yes, I completely removed the Tweeters and was getting no reading at all sadly. I believe the speakers were stored for a long time in shed, and while the cabinets have held up very well I think the damp has caused the tweeters to give up the ghost. It would be great if they are fixable, although it may be beyond my limited skillset! 

Good to know about the caps as well. I will certainly get those looked at once I know I have some working tweeters. 

I must admit I'm new to Acoustic Research speakers, but really hoping I can get these up and running again and sounding as they should. I'm  hoping for really good things! 

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Thanks for the heads up on a UK supplier. I must admit though that I'm a bit of a loss with which caps I should purchase, it's certainly not an area I know anything about it. Perhaps given my complete lack of knowledge I should take to my local tech guy. Shame as it seems like a very easy job though, replacing 4 caps

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I replaced my caps with Alcaps tighter tolerance NPE caps from Falcon Acoustics. Personally I would not fit more exotic/expensive caps, but do the reading up about caps. I've been very pleased with the Alcaps. I think it is worth paying just a little bit extra for tighter tolerance caps if they have them available.

If you are handy with a soldering iron I would replace the caps yourself. What's the point of having some tech guy do them (at some cost presumably) when you may be waiting quite a while to hear them in spec with suitable fixed or replacement tweeters? Especially when you picked them up at a song. Most of my enjoyment came from from knowing I fixed them myself. 

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Thanks, yes I would very much like to do this myself. As you say it's as much about bringing these back to life myself, rather than somebody else doing it for me. My soldering skills are passable, but are not going to win any awards. So happy to do this myself, and as far as soldering jobs go this is a job that even a beginner like me can do. My only issues is complete lack of electonics knowledge! So have no real clue as to what I'm ordering, it's another language to me. So you're right I need to do a bit reading up around caps and try and getting a better understanding of it all. 

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If you replace like with like, having little knowledge of capacitors will not be a drawback. From your picture I think I can read (upside down) that the top capacitor has a value of 20MFD (20 microFarads) and 50V (Volts). They will be NPE (non-polar electrolytic), so you cannot solder them the wrong way round. If you replace with 100V caps that will not hurt, but it would be wise not to replace with a lesser Voltage rating than 50.

If you are unable to source exact values as replacements then note that a 15MFD and a 5MFD wired in parallel will result in capacitance of 15+5 = 20MFD as required.  I cannot read the values on the other cap.

[Capacitors (in typical speakers) have values given in microFarads (sometimes written µF). It was common practice for capacitors to be marked as MFD or mFd either for machinery difficulty to produce the µ symbol print on the casing or for other manufacturer specific reasons.]

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Jeff gives sound advice 😉 (pun intended). It looks to me like the other cap is 14MFD. That's unusual, so if that's the case you have a couple of options: You could put 2 caps in parallel as Jeff described (12 + 2, 10 + 4, doesn't matter) or just use a 15uF cap. A capacitor +/- 10 to 20% is usually close enough.

Also, NPE caps as Jeff mentioned are fine. The originals were NPE. But for smaller values you could also use film caps. They cost more but last longer. Pay no attention to voltage ratings, as Jeff said, as long as it's over 50VDC but I want to mention film caps are often much higher voltage: 250, 450, even higher. Doesn't matter.

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PS: Don't spend a lot on caps. If you go with PartsExpress use either NPE or Dayton 250v poly.

Here's 10uF NPE https://www.parts-express.com/10uF-100V-Non-Polarized-Capacitor-027-340?quantity=1

10uF poly (oops. PE site not working at the moment but you get the idea)

Here's 15uf NPE https://www.parts-express.com/10uF-100V-Non-Polarized-Capacitor-027-340?quantity=1

and 15uF poly https://www.parts-express.com/Dayton-Audio-DMPC-15-15uF-250V-Polypropylene-Capacitor-027-432?quantity=1

Here's 20uF poy (or use two 10uF NPEs) https://www.parts-express.com/Dayton-Audio-DMPC-20-20uF-250V-Polypropylene-Capacitor-027-436?quantity=1

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Ah yes--forgot you're on the other side of the pond. I'm guessing Cornwall 🙂

So Falcon has the 20uF in both NPE (Alcap) and film (Solen). For the 16uF you'll have to use 2 values in parallel (Alcap, 8+8 or 10+6) or just use a 15uF Solen or, if you're really OCD put a 15 and a 1 in parallel.

FWIW I don't think I've ever removed the xo board to work on it. They're glued and stapled and prying one out will probably cause it to break. Working through the woofer hole isn't that bad and as Stimpy mentioned you can cut out the old caps leaving the leads (make little fish hook ends to attach the new caps. You still need to solder but this is way easier).

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