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Hello to all, So far I've have been happy just reading all the knowledgeable things people here have to say but now I have a question of my own I would like answered (which may or may not already be answered elsewhere here - in which case hopefully someone will be kind enough to direct me accordingly). I have a pair of Mission 720s which I have owned from day 1 (I purchased them in 1980). I have used them more or less continuously all these years. The mid range surrounds (the mid range as I understand it are Peerless K040-MRF) are separating / coming apart in a couple of places on the outer edge (pic below with lines on either sides of the split surrounds). I have more pics I can post if anyone wants to see more of what I'm talking about. This is affecting the sound quality. I am considering replacing the existing surrounds which are fabic (silk???) with foam surrounds BUT after reading many of the comments on this site it occurs to me that there may be some way to repair the damage (Permatex on the split, maybe) and keep the original surrounds which 'appear' to be in otherwise reasonable condition. Your thoughts and suggestions would be very welcome. Many thanks to you for taking the time to read this post and possibly answer my question.
Looks like one of my mids are bad and I am torn what to do. I have purchased caps to install and cleaned the pots. Upon testing the mids by an accomplished electronics guy (not me) he says sorry, I think your mid is shot. I trust his work. Do I look for a replacement mid (good luck)? Do I try to find someone to see if it can be repaired? Do I look for a replacement AR3 single speaker in the 60000 serial range? Do I give up and sell one working AR3 with one not working and wish years later I had a set of ar3's? This is a bummer!
The title gives the goal of this project. Here are three midranges: A: B: C: A is my uninjured midrange, B is the patient, a working midrange that came to me naked, as you see. C is a non-functional midrange that tests open, and is the donor. The hope is to make B look and sound like A. The hard part here is getting the parts wanted off of C. They are glued down tight. Further, on the donor unit, the grill is inset from the outer flange. This is different from my OEM units, on which the whole face is flush, and is making things harder. I'm willing to be destructive with the donor unit if necessary, but I'd rather not in case it's fault is actually repairable.... My idea at this point is to unscrew the four screws on the face of the donor. I expect this will enable me to pry-off the outer flange, the grill, and the damping, as a unit. X-acto chisel expected to be of use. I will then be able to cut around the inside of the flange with a utiltiy knife, removing the grill and damping. Does this approach sound OK? Advice from anyone who's had these drivers apart very welcome.
I have a beautiful pair of AR 2a that look like they just came out of their original boxes. They are all original, as far as I know. There are 2 problems with each speaker which I'd like to fix so that the speakers become (nearly) perfect: 1) Tweeter output is very soft, which I assume is due to dirty pots, and 2) There are a few tiny, 1/4" tears in the delicate midrange cones which I'd like to repair even though the tears are not audible. Inside, I expected to see the common, black & white Aetna-Pollak pots, but these are very different: they're much larger in diameter, they appear to be all-metal, they're perfectly quiet and rotate with a feel as smooth as silk, making me wonder if they're dirty at all. They're labled "Violet B150 AT4011", and appear to be original, although I've never seen this different type of pot before. Rotating them does not alter tweeter output level at all, making me think they're dirty, but they sure feel smooth and not dirty or corroded. They are not as easily removed as the A-P pots, in fact, it is not obvious at all how to remove them as they are firmly seated even with the rear, outside nut removed. They seem to be glued in place, though no glue is obvious. The midrange pots work fine and are perfectly quiet. Are these pots likely to be the culprit given that they are different from the A-Ps and appear to be of much higher quality? If so, what's the best way to remove them? Then, I'd like to use some kind of flexible coating on the midrange paper to seal the little tears from the outside. Would the red Permatex gasket compound work? Getting to the inside, behind the cones, is a bit of a problem due to both a) very short midrange wires and lots of fiberglass stuffing inside the midranges so patching the cones from the rear is not too likely. Your comments & suggestions are appreciated.