91% Isopropyl Rubbing Alcohol to clean potentiometers?


DW
 

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek 577 with dirty horizontal and vertical display controls, I have used this to clean residue on circuit boards and grime off surfaces and it works quite well so I was wondering if it could be used to clean the dirty potentiometers on the 577 curve tracer. 91% seems the best the best I can find. I also have a can CRC Lectra Clean. What are your thoughts, recommendations? Thanks


Bill Carns
 

If you go to a pharmacy and talk with the Pharmacist, they can give you IPA with a higher percent IPA and less water. This is better for pots, but be careful to not saturate. Sometimes you can damage the carbon resistance layer that is laid down for the wiper to run on. I am not sure if that is true for the ones TEK uses.

Bill

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of wilson2115@outlook.com
Sent: Tuesday, March 05, 2019 7:13 PM
To: TekScopes@groups.io
Subject: [TekScopes] 91% Isopropyl Rubbing Alcohol to clean potentiometers?

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek 577 with dirty horizontal and vertical display controls, I have used this to clean residue on circuit boards and grime off surfaces and it works quite well so I was wondering if it could be used to clean the dirty potentiometers on the 577 curve tracer. 91% seems the best the best I can find. I also have a can CRC Lectra Clean. What are your thoughts, recommendations? Thanks


Richard Solomon <dickw1ksz@...>
 

I prefer De-Oxit Fader Lube.
Works great.

73, Dick, W1KSZ

On Tue, Mar 5, 2019 at 6:12 PM <wilson2115@outlook.com> wrote:

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek
577 with dirty horizontal and vertical display controls, I have used this
to clean residue on circuit boards and grime off surfaces and it works
quite well so I was wondering if it could be used to clean the dirty
potentiometers on the 577 curve tracer. 91% seems the best the best I can
find. I also have a can CRC Lectra Clean. What are your thoughts,
recommendations? Thanks




DW
 

Thanks, I will check into that. Ideally, what would be the best solution I should use. Perhaps maybe I could run the pots back and forth about 500 times.


DW
 

Thanks


Don A
 

Deoxit is the best product I have found. Use it all the time on old audio
gear with scratchy pots
Don

On Tue., Mar. 5, 2019, 8:12 p.m. , <wilson2115@outlook.com> wrote:

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek
577 with dirty horizontal and vertical display controls, I have used this
to clean residue on circuit boards and grime off surfaces and it works
quite well so I was wondering if it could be used to clean the dirty
potentiometers on the 577 curve tracer. 91% seems the best the best I can
find. I also have a can CRC Lectra Clean. What are your thoughts,
recommendations? Thanks




Bob Albert
 

I think isopropyl alcohol is so mild it not only isn't likely to damage anything but also isn't likely to do much good either.  I quit using it long ago due to lack of results.
In the old days it was carbon tetrachloride.  When that was yanked off the market it was replaced by another chemical whose name eludes me at the moment.  When that was made illegal its replacement was 1,1,1 trichlorethylene that got banned.  That's the best one I ever used and I still have enough of it to do any cleaning jobs.
I have used denatured alcohol with varying success.  Acetone is a last resort; it's very powerful.  Brake fluid is potent as well and I wouldn't use it on anything without the utmost care.
I see there is something called de-oxit but I am skeptical.  I haven't used it, and it seems overpriced.  (Of course, WD-40 is less than worthless for this or, for that matter, for anything electronic.)
The problem with a noisy pot can be due to various causes, dirt being an infrequent one.  I think it's often corrosion/oxidation of the wiper surface, although sometimes it's wear and tear of the carbon element surface (for frequently used controls).  If the pot is used infrequently it's more likely chemical action.  Also corrosion of the interface between the wiper terminal and the wiper.
More often than not, simply exercising the pot solves the problem.  Just rotate the knob at least a couple hundred times.  Find the bad spot and put it there, then twist back and forth until your wrist aches.  When you recover, do it again.  I can't tell you how many times this has solved pot noise problems for me.  Perhaps it's a weak spring in the wiper mechanism.
Some circuits are poorly designed in that there is unnecesary dc flowing in the element.  A leaky blocking capacitor also can cause dc that creates noise when there is no signal.
So the answer, as usual, is that there is no simple answer.  It depends.
Bob On Tuesday, March 5, 2019, 5:38:15 PM PST, Richard Solomon <dickw1ksz@gmail.com> wrote:

I prefer De-Oxit Fader Lube.
Works great.

73, Dick, W1KSZ

On Tue, Mar 5, 2019 at 6:12 PM <wilson2115@outlook.com> wrote:

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek
577 with dirty horizontal and vertical display controls, I have used this
to clean residue on circuit boards and grime off surfaces and it works
quite well so I was wondering if it could be used to clean the dirty
potentiometers on the 577 curve tracer. 91% seems the best the best I can
find. I also have a can CRC Lectra Clean. What are your thoughts,
recommendations? Thanks




Richard Solomon <dickw1ksz@...>
 

Just don't cause a spark !!

73, Dick, W1KSZ

On Tue, Mar 5, 2019 at 6:41 PM <wilson2115@outlook.com> wrote:

Thanks, I will check into that. Ideally, what would be the best solution I
should use. Perhaps maybe I could run the pots back and forth about 500
times.




Chuck Harris <cfharris@...>
 

IPA won't help the problem with noisy pots.

Pots get noisy for several reasons:

In the cheaper pots that have deposited carbon elements,
the noise is often caused by the wiper grinding its way
through the carbon, and leaving holes. These can sometimes
be fixed by moving the wiper to touch other parts of the
element... but the accuracy of the pot is already compromised.

Some cheaper pots have the insides open to the outside,
and are dust magnets. A naptha (lighter fluid) wash and
lube job will help.

In more expensive pots, the noise is caused by the
lubricant getting hard, and lifting the wiper off of the
resistance element. Again naptha to clean and a pot
lube to lubricate.

I use DeOxit Fader lube for most pot elements. There is
also a DeOxit synthetic grease... one of the PPA's, but I
haven't tried it yet.

99% IPA becomes 91% IPA shortly after the bottle is opened.

IPA is good for a lot of things, but it is weak at removing
old grease and pot lubricant. Use naptha.

-Chuck Harris

OBTW, 91% IPA is fine for flux removal on PCB's.



wilson2115@outlook.com wrote:

I have some 91% Isopropyl Rubbing Alcohol sitting around and I have a Tek 577 with dirty horizontal and vertical display controls, I have used this to clean residue on circuit boards and grime off surfaces and it works quite well so I was wondering if it could be used to clean the dirty potentiometers on the 577 curve tracer. 91% seems the best the best I can find. I also have a can CRC Lectra Clean. What are your thoughts, recommendations? Thanks




Bill Carns
 

Well, the danger there is if it is dying from deterioration of the element, then that will only make it worse.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of wilson2115@outlook.com
Sent: Tuesday, March 05, 2019 7:41 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 91% Isopropyl Rubbing Alcohol to clean potentiometers?

Thanks, I will check into that. Ideally, what would be the best solution I should use. Perhaps maybe I could run the pots back and forth about 500 times.


Brendan
 

Deoxit D5 or DN5 followed by fader lube is what I do. The D5 gives it a good washout and the fader lube adds some lube hence the lube part of the name.

On Tue, Mar 5, 2019 at 07:56 PM, Bill Carns wrote:


Well, the danger there is if it is dying from deterioration of the element,
then that will only make it worse.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
wilson2115@outlook.com
Sent: Tuesday, March 05, 2019 7:41 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 91% Isopropyl Rubbing Alcohol to clean
potentiometers?

Thanks, I will check into that. Ideally, what would be the best solution I
should use. Perhaps maybe I could run the pots back and forth about 500 times.




Jared Cabot
 

Another vote for Deoxit products, always had good experiences with them.


Richard Knoppow
 

A better cleaner for pots is Caig Faderlube. It has a little lubricant in it and will not attack the resistance strips. Also works on wire wound pots.
Another place to get dry IPA is at a computer store or department. They usually have 99+% in either bottles or spray cans. IPA absorbs moisture until it becomes 91% which is why its not usually stocked in the dry form. Dry IPA will become 91% if exposed to the air for very long. I think the spray can version probably stays dry for longer than the bottled kind.

On 3/5/2019 5:28 PM, Bill Carns wrote:
If you go to a pharmacy and talk with the Pharmacist, they can give you IPA with a higher percent IPA and less water. This is better for pots, but be careful to not saturate. Sometimes you can damage the carbon resistance layer that is laid down for the wiper to run on. I am not sure if that is true for the ones TEK uses.
Bill
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL


DW
 

I rocked the horizontal and vertical controls until my fingers and wrist got sore while passing the time with some EEV blog videos, problem resolved and the stickiness has gone away, thanks for all the help!


Frank DuVal
 

I hope you mean brake cleaner, as brake fluid comes in two types, neither of which seem good for inside of potentiometers....  one Glycol based and the other a synthetic base both with a viscosity greater than water.

Yes, brake cleaner is very aggressive, just like carburetor cleaner. I would not use it around plastic until I tried it on a sample disposable part.

Cleaning tuners and volume controls was standard service back 30 years ago. Many spray chemicals for the job. Using that little red straw got the cleaner into the pot well.

But, using that spray on fader controls rendered them bad instantly! Not a great lesson to be learned by trying.

Another vote for DeOxit (Caig) Fader cleaner.

Frank DuVal

On 3/5/2019 9:02 PM, Bob Albert via Groups.Io wrote:
I think   Brake fluid is potent as well and I wouldn't use it on anything without the utmost care.





Don A
 

Caig fader lube had a name change to deoxit fader lube a few years back.
Terrific product designed specifically for this task.
There also a product for cleaning switch contacts deoxit D5. Also fantastic.

Yup you will pay a few bucks for a can but they last forever through
countless projects.

My thoughts
Don


On Wed., Mar. 6, 2019, 12:20 a.m. Frank DuVal via Groups.Io, <corvairduval=
netscape.net@groups.io> wrote:

I hope you mean brake cleaner, as brake fluid comes in two types,
neither of which seem good for inside of potentiometers.... one Glycol
based and the other a synthetic base both with a viscosity greater than
water.

Yes, brake cleaner is very aggressive, just like carburetor cleaner. I
would not use it around plastic until I tried it on a sample disposable
part.

Cleaning tuners and volume controls was standard service back 30 years
ago. Many spray chemicals for the job. Using that little red straw got
the cleaner into the pot well.

But, using that spray on fader controls rendered them bad instantly! Not
a great lesson to be learned by trying.

Another vote for DeOxit (Caig) Fader cleaner.

Frank DuVal

On 3/5/2019 9:02 PM, Bob Albert via Groups.Io wrote:
I think Brake fluid is potent as well and I wouldn't use it on
anything without the utmost care.







Roy Thistle
 

Hi:
Lots of companies sell it. I see it on Amazon for 13.00 U.S. a gallon (4, 1 quart plastic bottles.) It is very hydroscopic (absorbs water from the air readily)… so unless you store it over a drying agent, it will tend towards 90%, as it picks up water, from the air that gets into the bottle.
The main advantage of IPA is it is cheap (really cheap compared to proprietary cleaners, like Deoxit). But, another significant advantage is that it is a pure (other than the little bit of water)… it is a pure chemical. So, you know what you are using, and can find out what it will do to what you are using it on (That part needs some research, or advice.). You can get (download) the Material Safety Data Sheet (MSDS), so you can determine how it will affect you, how to use it safely, and how it will affect the environment. The MSDS for many proprietary cleaners don't significantly identify what's in them (it's proprietary).
Regards


Bob Albert
 

For the general information of the group, here is a link to determine characteristics of various solvents, etc.  It provides more information than you will ever want to have.
The Most Complete Free Material Safety Data Sheet (MSDS) list of chemical information on the Internet


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Looking for MSDS information regarding the chemicals in a commercial product or a material safety data sheet (MS...
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On Wednesday, March 6, 2019, 11:16:45 AM PST, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

Hi:
Lots of companies sell it. I see it on Amazon for 13.00 U.S. a gallon (4, 1 quart plastic bottles.) It is very hydroscopic (absorbs water from the air readily)… so unless you store it over a drying agent, it will tend towards 90%, as it picks up water, from the air that gets into the bottle.
The main advantage of IPA is it is cheap (really cheap compared to proprietary cleaners, like Deoxit). But, another significant advantage is that it is a pure (other than the little bit of water)… it is a pure chemical. So, you know what you are using, and can find out what it will do to what you are using it on (That part needs some research, or advice.). You can get (download) the Material Safety Data Sheet (MSDS), so you can determine how it will affect you, how to use it safely, and how it will affect the environment. The MSDS for many proprietary cleaners don't significantly identify what's in them (it's proprietary).
Regards


Bob Albert
 

It looks like the link has been filtered out.  Just google the title.
Bob

On Wednesday, March 6, 2019, 11:55:07 AM PST, Bob Albert via Groups.Io <bob91343=yahoo.com@groups.io> wrote:

For the general information of the group, here is a link to determine characteristics of various solvents, etc.  It provides more information than you will ever want to have.
The Most Complete Free Material Safety Data Sheet (MSDS) list of chemical information on the Internet


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The Most Complete Free Material Safety Data Sheet (MSDS) list of chemica...

Looking for MSDS information regarding the chemicals in a commercial product or a material safety data sheet (MS...
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    On Wednesday, March 6, 2019, 11:16:45 AM PST, Roy Thistle <roy.thistle@mail.utoronto.ca> wrote:

Hi:
Lots of companies sell it. I see it on Amazon for 13.00 U.S. a gallon (4, 1 quart plastic bottles.) It is very hydroscopic (absorbs water from the air readily)… so unless you store it over a drying agent, it will tend towards 90%, as it picks up water, from the air that gets into the bottle.
The main advantage of IPA is it is cheap (really cheap compared to proprietary cleaners, like Deoxit). But, another significant advantage is that it is a pure (other than the little bit of water)… it is a pure chemical. So, you know what you are using, and can find out what it will do to what you are using it on (That part needs some research, or advice.). You can get (download) the Material Safety Data Sheet (MSDS), so you can determine how it will affect you, how to use it safely, and how it will affect the environment. The MSDS for many proprietary cleaners don't significantly identify what's in them (it's proprietary).
Regards


Roy Thistle
 

Hi:
I think that high concentration IPA might... but only after prolonged contact (like soaking a part in it, in a closed container) partly dissolve some of the binders, or plasticizers, in rubber or plastic parts (Some of those are to a degree soluble in IPA.) . IPA is, to some extent, going to attack natural shellacs, varnishes, and lacquers (IPA might be similar to the solvents they use.). So caution might be advisable with old electronics, that might have used these in their manufacture.

Most of the chemicals that Bob mentions are de-greasers. As Bob points out acetone (in some nail polish removers) is a strong degreaser (Usually used on bare metal because it can dissolve, or weaken, some plastics, and paints.) Of all the strong degreasers Bob mentions, acetone is available, and is not very toxic (though good ventilation is necessary, and no sparks or flames).

There are also chemicals that are de-oxidizers, anti-oxidants, and lubricants (usually just being one of those kinds of things.) Some "cleaners" claim to be all those things. In other threads there were discussions about the different kinds of Deoxit, for sale. I don't use it. And, I don't know about it. So, I am not saying it works, or it doesn't... I don't know. But, I am listening and researching. The main things that turn me away from "cleaners" is I don't usually know what is in them (So, I don't know what I am using.) That and, the amount of woo around them. They are expensive too. And some of that might be just because people might not know how cheap and available, the chemicals that they use, are (because we don't know what is in them.)

WD40 is a different thing. I think it is mostly a water displacement compound... and, it is very good at that... for driving water, or moisture, out of closely fitting parts. It does clean, or dissolve too. And it will lubricate (at least temporarily... the liquid lubricant (low viscosity petroleum distillates and very fine mineral oil?) evaporates fairly quickly, and leaves a white residue (not sure if the white stuff has lubrication properties.) I have used it to free really stuck potentiometer shafts, where they pass through the bushing... the WD40 runs easily into the busing, and some mechanical force frees up the shaft. I don't like to use penetrating oil. It is kind of a last ditch thing to try, if other methods fail to unseize the shaft... and sometimes nothing seems to work too.

As Bob mentions.... I've had good success with "exercising" a "scratchy" pot too.
Regards