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

Infinty Quantum 2

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Best regards, Fred
 
Good afternoon,

Normally I use the Kontakt spray do get rid of the oxidation etc. First I use Kontakt spray, let it work for about a quarter of an hour, and then the switch takes a alcohol batch for a half an hour. Clean it meanwhile with a small brush. I don’t use Kontakt spray afterwards. This is because all kind of spray’s except for Videospray, get dusty after a while. The contact-spray is sticky and attracting all kind of filth out of the air, and makes the problem come back. That’s at least my opinion ;-).

Best regards, Fred
 
I used the salt and vinegar solution to get most of the corrosion of my pots, then I have a friend who works in a jewelry store and they were able to polish the pots on their polishing wheel! worked great!!
You may have to search for a jeweler who is willing to polish non jewelry items though.
Good luck!
 
Nicely detailed procedure. However, there are a couple of things to comment on:

  1. Sometimes (as in my case) the wiper for the pot (the part that rubs on the coils) has corroded away, or the button on the wiper is corroded away. I was able to fix one with a bead of solder (see before and after photos below) but Vintage-AR store on eBay sells a decent replacement pot for only $15. If yours is too far gone, I suggest buying a brand new one!
  2. You did not discuss replacement of the old OEM capacitor. I replaced the old cap in my AR4x's with brand new audio grade caps and was astounded by the results. Bass and Treble were clear, crisp and coming from the right speaker. I suggest that while you have the speaker apart, that replacing the capacitor is a no-brainier. FYI - you can leave the old one in place, just clip the wires!

upload_2015-10-9_9-41-46.png upload_2015-10-9_9-39-37.png
 
Couple of things to this useful thread:

First, the Permatex spray diversion -
post 8 Permatex on the pot.
post 28 Permatex was applied too heavily, inferring that it was mis-applied
post inferring the redoping was discussed by the OP (it wasnt)
post 45 mistakes that Permatex was on woofer surrounds
post 59 says not to use Permatex​

Second, the worn-away contactor -
a music instrument repairman would do the silver solder or brass insert much cheaper than a jeweler (used to working in expensive things)
 
Amazing write up! Thank you.

Looking to try this out next weekend. Any chance a PDF of this write up exists? It looks like the photos are down.
 
A tremendous write-up. I actually bypassed the potentiometer altogether but even still, there was so much useful info here it was insane. Thank you.

My bypass write-up is here.
 
This thread is what gave me the ambition and confidence to tackle a pair of AR4x and a pair of AR2ax. Both pairs had been sitting in my storage room for several years and I had pretty much forgotten that I even had them. Now I have 2 pair of wonderful speakers instead of just space eaters.
Thanks!
:biggrin:
 
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