Recommended Cleaning Method - Sherwood S-7100A Volume Pot

MCM_Fan

MCM_Fan

AK Subscriber
Ok, I've googled this topic several times and read everything I can find in this and other forums. I am well aware of the warnings: Do NOT use Deoxit on the volume pot of the Sherwood S-7100A, or other Sherwood receivers that have the on/off switch integrated with the volume control.

It is well documented that Deoxit, and other cleaning solvents make the plastic on the on/off switch brittle, leading to irreparable failures. I understand the problem, and I am well aware of the work arounds for a failed switch. Believe me, those are easy to find using google.

I am one of the lucky ones that has a Sherwood S-7100A with a working on/off switch. My problem is the volume pot REALLY needs cleaned. It is VERY noisy.

So, what is the recommended way to clean this volume pot without destroying the on/off switch? I haven't been able to find a single recommendation, just the warnings against using Deoxit or other solvents, the work arounds for failed switches and a few people that said just live with the noisy volume pot.

Does anyone have a proven method of cleaning the pot without damaging the on/off switch? Would something like isopropyl alcohol work, or would that also make the plastic (polycarbonate) in the switch brittle and prone to failure? What about disassembly and manually cleaning the contacts with some 600 grit (or higher) emory cloth, or polishing them with a pencil eraser?

Other than the noisy (and I mean REALLY noisy - worst I've ever heard) volume control, this little Sherwood is a great sounding vintage receiver. I'd really like to get rid of the noise in the pot without damaging the switch.
 
"DeOxit" is usually used as a general term vs. a specific product. What I use is DeOxit D5 on rotary and toggle switches. I don't use D5 on pots.

I use DeOxit D100 (no solvents) on pots - most of which are Alps, and I believe plastic - and have not destroyed one. The spray can for the D100 uses a metered valve so only a small amt is dispensed when you push the button. It works very well and usually 1 or 2 well aimed shots shuts it up.

See what others have to say.

http://store.caig.com/s.nl/it.I/id.66/.f
 
If I was in your predicament I'd consider this treatment.

The pot has 3 sections:-the front 2 are the volume - left and right. The rear section is the switch.
If I was in your position I would go for the non aerosol variety of Deoxit gold
or even
http://www.corrosionx.com.au/corrosionx-aviation.html

Only need a drop in the volume section and let it work in slowly. Let it take its time.
Stay clear of the rear switching pot for now.
 
Solvent is bad for vintage and nylon plastic parts. I wouldn't use solvent near a PCB either. I use MG Chemicals residue free cleaner available at Fry's. Twice the can for half the price. The lubricant version is 100 percent volatile and does not leave behind residue.
 
Search for the "official' DeOxit thread. There are multiple products out there--D5 (red) for cleaning and F5 (green) for lubrication/restoration. Use accordingly.
 
gort69 said:
"DeOxit" is usually used as a general term vs. a specific product. What I use is DeOxit D5 on rotary and toggle switches. I don't use D5 on pots.

I use DeOxit D100 (no solvents) on pots - most of which are Alps, and I believe plastic - and have not destroyed one. The spray can for the D100 uses a metered valve so only a small amt is dispensed when you push the button. It works very well and usually 1 or 2 well aimed shots shuts it up.

See what others have to say.

http://store.caig.com/s.nl/it.I/id.66/.f
Click to expand...

Gort69 is correct. If you are looking for cleaning solution WITHOUT solvent, please use DeoxIT D100S-2 spray. It doesn't have solvent in it so it is safer to use for plastic parts.
It also will provide more lubrication than DeoxIT D5 spray.
Please check out this video showing the difference between the DeoxIT sprays:
http://store.caig.com/s.nl/it.I/id.101/.f?sc=17&category=-117
 
Thanks to all for the replies. I have a number of recommendations for cleaners that are safer for plastic than my usual Deoxit D5. These include Deoxit D100, LPS-1 and MG Chemicals residue free cleaner. In theory these should be gentler on my Sherwoood S-7100A poly carbonate on/off switch. Has anyone actually used any of these on a Sherwood S-7100A (or similar Sherwood model with the on/off switch integrated into the volume pot)?

Given the fact that I seem to be one of the lucky few with an actual working on/off switch on my S-7100A, I don't want to be a guinea pig. I don't want to be the first to try something that should work. I'm looking for actual verified solutions. Not trying to sound ungrateful for the suggestions, but better safe than sorry. Once that switch is damaged, there is no going back and replacements are unobtanium.
 
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I am not familiar with the physical construction of that switch. But on some pots there are openings which allow access to the wipers. I have sometimes been able to apply small amounts of D100L (the liquid form which comes in a bottle with a needle type applicator). IMHO the ideal applicator would be one of the small foam Caig swabs. The problem is if you don't have any of those, it may be difficult to get them in a small quantity. I would not try sticking a q-tip inside there. The needle point applicator is OK but you would be better able to control amount and placement of the fluid with the swab. All of this is moot if there are not appropriate access holes in the pot. Another thing to consider is removal of the pot if that would allow improved access.

Just tossing out ideas. I appreciate your cautious approach...

If you are able to avoid allowing any cleaning products (regardless of which one) to come into contact with the switch area you should be good I think.
 
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Good news. I was able to clear up the scratchiness in the volume pot just by vigorously working it back and forth several times. No solvents or disassembly required.

I do need to clean the rest of the pots and switches however. Both the input selector and speaker selector switches are noisy as all get out even cut in and out when changing settings. I had a vintage Yamaha receiver once that had the same problem with the input selector and the regular Deoxit D5 cleaned it right up.
 
MCM_Fan

I have the S-7200 which was suffering from the same noisy volume pot. I cured it in exactly the same way you did; just by working the pot it between its min/max for about ten minutes. This was over a year ago and it's been crackle-free since. So hopefully you'll be good for a long while before you get any more noise.
 
Binkman said:
I posted the 'vigorous' cleaning method in my reply.
http://www.audiokarma.org/forums/index.php?threads/sherwood-s-7100a-advice-wanted.575026/
http://www.audiokarma.org/forums/index.php?threads/sherwood-s-7100a-advice-wanted.575026/
I have an 8600a and applies to all circa era w/ said switch. Good advice? don't screw with the switch or the pots. PERIOD. :D
Click to expand...

Also from that thread:

"The selector and speakers switches responded to DeoxIt".

Sounds promising for my remaining issues. I'll try to open it up and clean the input and speaker selector switches tonight. If I can get those working properly, I will have a 100% functional S-7100A.
 
MCM_Fan said:
Also from that thread:

"The selector and speakers switches responded to DeoxIt".

Sounds promising for my remaining issues. I'll try to open it up and clean the input and speaker selector switches tonight. If I can get those working properly, I will have a 100% functional S-7100A.
Click to expand...

Well, 100% functional, but not complete. I am missing one of the small knobs. I'll need to locate one of those.
 
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