Acoustic Research Potentiometer Restoration Guide (VERY LONG, with photos)

Nicely done. A few suggestions:

Salt is cheap. Use a lot.

After removing the parts from the vinegar-salt slurry, wash them with water and a mild dishwashing detergent. You don't want any salt or acid deposits left on the metal, and I'm not sure you can depend on DeOxit to remove either completely.

Have one of these around: http://www.contenti.com/products/brushes/150-040.html The bristles can get into places that the Dremel wheel sometimes misses. Wear gloves when using it.

Coat the newly-cleaned windings and wiper with a dielectric grease to smooth operation and help retard recorrosion. I use this: http://store.caig.com/s.nl/it.A/id.2494/.f?sc=2&category=185 One 2g tube is enough to coat four pots if you don't go overboard.

There have been some incidents of those wire nuts being shaken loose after speakers are closed up. I like to use a nut to get a good, tight twist on the wires and then remove it and solder them.
 

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I would be careful to not let the wirenuts touch the cabinet walls as they may vibrate when music is played.
 
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STEP THIRTEEN: RESEAL THE SPEAKER

A Sticky Situation
What we need to do now is to ensure that there is an airtight seal in between the woofer and the front baffle. We do this by using 3M Strip-Calk.

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3M Strip-Calk is an automotive product used to seal vehicles in places where air or moisture could enter. Not surprisingly, it also works wonders on speaker baffles. Let's give it a go.

(NOTE: 3M Strip-Calk is very sticky. This is good for what we want to use it for, but bad for our hands. If it sticks to your hands too much, don't grasp it so hard. Also try just tapping it into place rather than holding on to it for too long.)

When you open the box you'll be presented with a sight like this.

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What you want to do is to separate each individual strip without stretching it. Once you've got one strip pulled apart from the rest, begin to lay it down around the baffle where the woofer will sit.

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As you're laying down strips, mark where the screw holes are in the baffle - otherwise it will be difficult to find them under all the Strip-Calk.

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Keep laying down strips until you've covered the entire circumference of the woofer cutout twice around.

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Screw This!
Take the woofer (I swear, you'll be thanking yourself for that extra wire length for the rest of your life) and set it down into the cutout, making sure to line up with the screw-hole marks you made earlier.

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Take one screw and fish it around a bit inside the screw hole until you find the threads underneath. Take your power drill and screw it in most of the way. Be careful how hard you push, as the T-nut that holds the screw can slip (that is a very unfortunate situation).

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After you have the one screw most of the way in, start the screw opposite of it. Repeat this process and continue tightening opposite until the woofer is securely in place.

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STEP FOURTEEN: RESTORE THE CABINET

ATTENTION: This step is OPTIONAL. If you do not wish to restore the cabinet, and just want to listen to some music, you may hook up the speaker and go at this point.

Former Glory
At this point in the process, the electrical and acoustic restoration of your speaker is complete. However, what's a nice-sounding speaker without some good looks to go with it?

Howard's Restor-A-Finish and Howard's Feed-N-Wax are your friends here. Grab a rag or two also.

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Since I have already made a video tutorial for a Howard's restoration, I figured that I wouldn't photo document the whole process and just link to that tutorial. Here it is:

Howard's Speaker Cabinet Restoration - A Video Guide

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CONCLUSION

Congratulations! You have successfully restored your AR speakers to working order. Go hook them up and enjoy!

There are a few other things that you can do, but that I have not documented:

Replacing capacitors. Capacitors tend to drift in value with age, so replacing them will bring the speaker closer to its factory specifications. Find the value of the capacitor(s) in your speaker and order the caps of your choice. Use the soldering, wire cutting, etc. skills you have learned from this thread to accomplish a capacitor replacement.

Cleaning the grille cloth. In order to clean the grille cloth, you will need to carefully remove the fabric from the frame by removing the staples. Be careful, as the frame has become brittle with age. An overnight bath in Woolite will do the trick. When putting the fabric back on, use the lowest-powered stapler you own, or just glue it on with clear-drying tacky glue. If the cleaning does not go well, it is possible (but somewhat expensive) to order replacement grille fabric and frames from online dealers.

That's about it!

I would like to thank members gkimeng, RoyC, and Zilch for suggesting corrections and improvements to this guide. Nobody's perfect (much less me), and so if you find an error, inconsistency, etc. with this guide, please don't hesitate to let me know.

Thank you, and enjoy your AR speakers!
 
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VERY WELL DETRAILED!! I have done many dozens of these- the level controls always a problem. After I clean and polish the level controls (as you instructed) I usually super glue the swiper arm into place on the two pins so it does not shift while being put back together. Another thing I do to keep the insulation from invading back into the level pads is to staple a plastic bag over the level pad area to prevent the re-migration of the insulation back into the pads. It seems to work fine!
I sometime will remove the grill clith from the frame, wash in Woolite on gentle then restaple back to the frame. Looks brand new in most cases BUT is labor intensive pulling all those staples!!
Appreciate you posty here- you are certainly helping with great pics and much detail!!
DC
 
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I was with you until the Permatex application...That is way too much. If it is determined to be needed at all, it should be diluted (at least 50-50) with lacquer thinner...and applied sparingly.

Your stuffing is not the nasty, earlier rockwool. The yellow, clumped stuff in your speakers is fiberglass, and much easier to work with.

I am glad to see the wire nuts...very practical. They often get a bad rap by audio gurus. There aren't any to be found in AR speakers, but 40 year old KLH speakers are full of them, and I have never seen one fail.

Original type grille cloth, identical to the original, is available if grille cloth removal and cleaning does not go well.

Very nice photos and guide!

Roy
 
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Very nicely done! Thanks for all the effort you put into this thread. I only have one question. Who's "NORM"? :)
 
Man , you have entirely too much time on your hands ! :D
Great detailed description though !!! :thmbsp:
Keep it up Brother !!!!!:smoke:
 
Tmad40blue - you are very talented - I wish half of your ability - superb post - I am saving this one.
 
Lovely fabulous work, you can open your own business for restoring AR gear for sure.

Keep it up.... :thmbsp:
 
Great tutorial! :thmbsp: Gonna refurbish my pair this fall and this thread will certainly help.
 
I have a suggestion.... instead of drawing the diagram... let's take a picture... with your phone or digital camera... :D

This is helpful for newbie like me... taking pic of where we may mess up later on :smoke:
 
Nice detailed description and photos. I have a pair of AR4's that need this treatment. Thanks.
 
Thanks for writing this up, this thread will get a lot of visits I'm sure!

Scott
 
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