CurtPalme.com Home Theater Forum

**ecrabb** · Posted: Sat Nov 24, 2012 5:07 pm Post subject: Fixing scratchy pots...

Here's one for Curt or Mac...

My old man has a pretty nice harman/kardon two-channel setup: Amp, preamp, EQ, cassette deck, and turntable. I think it's probably '83 vintage, and a really nice setup. He just remodeled the room it's in and got a nice new piece of furniture for it all to sit in, but the problem is pretty much all of the pots and switches have gotten pretty rough, some to the point that it's hard to even get the left channel to work sometimes. I know it's just oxidation, and not worn switches/pads, because this system has seen very little use over the years.

So, the question is... Will Deoxit fix the issues, or is this going to require a tear-down and refurbishment/replacement of the switches and pots? If so, are those pots even available with the right shaft lengths, etc.?

I told my old man I'd ask you guys for him.

As always, thanks for your advice!

SC

PS - Here's a photo I found on the web of the kit in question:

**Curt Palme** · Posted: Sat Nov 24, 2012 5:11 pm Post subject:

If Caig doesn't do it, nothing will, and good luck finding replacements. Harman was known for bad pots, so was Yamaha. 99% chance that a bottle of Caig will do it. Use it SPARINGLY though, that's the key!

macgyver655 · Joined: 22 Aug 2007 Posts: 7054

WD40. Juice it up good while rotating. Use a cloth to soak up the excess. Just did my power amps last week including the input and output connections. Perfection.

**Curt Palme** · Posted: Sat Nov 24, 2012 6:11 pm Post subject:

Really Mac? I'd do the Deoxit first over WD, but that's just me...

macgyver655 · Joined: 22 Aug 2007 Posts: 7054

Nashou66 · Posted: Sat Nov 24, 2012 7:52 pm Post subject:

The Best stuff I have tried so far is Radio Shack Tuner cleaner.

It even cleaned the Thermostat for a deep frier at my Restaurant!! And thats a testament to its cleaning ability.

Athanasios

**Curt Palme** · Posted: Sat Nov 24, 2012 8:02 pm Post subject:

Yes, Caig leaves a lubricant Smile

Best stuff out there.

Nashou66 · Posted: Sat Nov 24, 2012 8:11 pm Post subject:

macgyver655 · Joined: 22 Aug 2007 Posts: 7054

Wouldn't it be funny if deoxit was the same stuff as WD40 just at 10 times the cost...... Laughing

**Curt Palme** · Posted: Sat Nov 24, 2012 9:20 pm Post subject:

Interesting. They don't have crap Shack here any more, Circuit City bought them all and pretty much nuked all parts type stuff.

Definitely the stuff that leaves a bit of silicone behind is preferable to the pure alcohol type stuff that completely evaporates. Still, I've had Caig clean pots that the cheaper stuff doesn't, so I don't even bother with the cheap stuff any more.

The only thing that Caig couldn't clean was a Rolls preamp out of a swimming pool. The music volume control went from 0 to full in 1/10 turn. I ended up replacing the control, and cracked the old one open. The control was cheaply made, and over time the carbon had worn out completely at the low volume end. Stupid pot was only 2 years old to boot. So that couldn't be cleaned, it was the carbon track that went bad.

**ecrabb** · Posted: Sat Nov 24, 2012 10:02 pm Post subject:

Thanks for all the input, guys!

OK, so next question... To clean the pots, do you just remove the component's cover and shoot into holes/crevices in the pots? The h/k components have a very satin-like finish on the faceplates. It almost resembles bare cast aluminum (but finer) or 500-grain sandpaper. So, I definitely wouldn't want to get anything on the faceplate.

BTW, here's an interesting thread on the WD-40 vs. contact cleaner question:
http://www.electronicspoint.com/safe-use-wd40-switch-potentiometer-cleaner-t13537.html

Don't really have much of an opinion one way or the the other on WD. One opinion is that since it contains a lubricant, the residue that's left behind after cleaning could attract dust and contaminants. That would be true of any product that contains a lubricant, though. The only way to avoid it would be to use a product that leaves zero residue. I would think the "residue" issue would only be a problem in certain (non-home) types of environments.

SC

macgyver655 · Joined: 22 Aug 2007 Posts: 7054

Ha, kinda reminds me of a lot of threads on here. A lot of back and forth with little substance. I particularly like this one:

It will leave oily film behind that dissolves the
grease in moving parts (which should stay in those parts) and
will attract dust.

Ahhh, doesn't grease attract dust also...... and won't any cleaner solvent remove the factory grease. And if it removes it then shouldn't a lubricating residue be left behind?

To funny.

I've seen many of these threads alike.

But yes, some manufacturers documents recommend WD40 for electrical contact repair. Of course this could of been before Caig deoxit was available.

I looked at some of the data sheets for both and aside from the 5% trade secret ingredient, they look pretty similar. But I didn't examine them real thoroughly......

Nashou66 · Posted: Sat Nov 24, 2012 11:10 pm Post subject:

Steve you have to get the cleaner into the Pot. So yes remove the cover, spray with the small straw into the holes of the pot and turn the pot spindle back and forth. That should do it.

I have used WD as well i just don't like the smell . And dust isn't a problem. WD forty was invented by the Australian Navy I believe.
It was the 40th iteration of the Water Displacement formula that worked best. I forgot how far in the number's they got . Wink

Nashou

macgyver655 · Joined: 22 Aug 2007 Posts: 7054

If Curt recommends the Caig then stick with that. I would not disagree. Very Happy

**ecrabb** · Posted: Sun Nov 25, 2012 12:46 am Post subject:

Will do, Mac. I'm not paying for it, so why would I care how much it costs. Wink

I'll have the old man pick up a can, and I'll pull the cover and give it a whirl when I'm there next month for Christmas.

Athanasios, I remember reading the story somewhere, and I'm pretty sure WD-40 was an American invention - a California guy, I believe, and very much commercial - not military.

SC

Nashou66 · Posted: Sun Nov 25, 2012 2:58 am Post subject:

CxTurbo · Joined: 13 Oct 2008 Posts: 388 Location: Ontario, Canada

WD-40 was being developed to prevent rust corrosion on Ballistic/Nuclear Missiles. It is an American that invented it.

See here for all you wanted to know on WD.

http://en.wikipedia.org/wiki/WD-40

**Curt Palme** · Posted: Sun Nov 25, 2012 6:43 pm Post subject:

Years ago one of my installers told me that some testing was done between WD40 and urine. In some cases, urine did more.

This was long before the internets, so I have no idea if it was true. I'll stick to the WD40, thanks!

Xeus · Joined: 07 Mar 2006 Posts: 111 Location: N.E. Wisconsin

A good read on cleaning pots and switches

http://www.audiokarma.org/forums/showthread.php?t=207005[url]

Matt
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**AnalogRocks** · Posted: Mon Nov 26, 2012 8:14 am Post subject: