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Tektronix Rescue Mission
Some Tektronix Equipment areas of opportunity to rescue:
I'm not going to be eating much this month. I invested in the Wavetek and Pacific Instruments 1038 (Tektronix 5000 series looks like compatibility) kits. They're spoken for or in route. I think the rest are available. Also, if anyone has any feedback regarding the Wavetek and Pacific Instruments 1038 systems I'd appreciate any suggestions, comments, thoughts, etc. regarding since there isn't much on the web relating to? Thanks in advance! |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Yes, WD-40 is dangerous stuff when used inappropriately. IT IS DEFINITELY
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not a lubricant. It is for water displacement as you say. If you use it on steel stuff, after it has done its freeing up or water lifting job, get it all off. Use another cleaner like Brake cleaner or one of the good electronic cleaners and then use oil if you need to lubricate. I saw a nasty demonstration one time. A guy in California took two raw steel plates - like maybe a drill press table of something un-plated, and he sprayed one with WD-40 and left the other alone. Then he went away for 6 months and left them out in the weather. The WD-40 kept doing its job alright. It kept attracting water and the plate with WD-40 rusted as bad as they come. Never ever leave it on steel. I use it occasionally (and yes, it is GREAT at getting seized older pot bushings going again) but I also know when NOT to use it - I hope. Bill -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Craig Sawyers Sent: Wednesday, March 06, 2019 4:29 PM To: [email protected] Subject: Re: [TekScopes] 91% Isopropyl Rubbing Alcohol to clean potentiometers? WD40 is a different thing. I think it is mostly a water displacementThere is a subculture of old Teleprinter collectors who have nothing good to say about WD40. If you use it to lubricate one of those supremely intricate mechanisms, it dissolves all the old gummy grease and deposits it in the moving parts. Which totally seizes the mechanism. The only solution is to totally strip the many hundreds of parts in the machine, clean every part and reassemble with correct lubricants. Craig |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Quite right. It isn¡¯t a lubricant, it¡¯s a water dispersant and nothing else - the key is in the WD! Water Dispersant No. 40.
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Robin On 6 Mar 2019, at 22:29, Craig Sawyers <c.sawyers@...> wrote:
WD40 is a different thing. I think it is mostly a water displacement compound... and, it is veryThere is a subculture of old Teleprinter collectors who have nothing good to say about WD40. If you |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Craig Sawyers
WD40 is a different thing. I think it is mostly a water displacement compound... and, it is veryThere is a subculture of old Teleprinter collectors who have nothing good to say about WD40. If you use it to lubricate one of those supremely intricate mechanisms, it dissolves all the old gummy grease and deposits it in the moving parts. Which totally seizes the mechanism. The only solution is to totally strip the many hundreds of parts in the machine, clean every part and reassemble with correct lubricants. Craig |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Very interesting ... the book is available as PDF FYI
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There is also a "trimmer primer" which I found interesting. Dave On 06/03/2019 22:03, Roy Thistle wrote:
Hi All: |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Hi All:
There are three kinds of pots in common use, that I remember about: these are wire wound, carbon film, and plastic film. Also, there are ceramic film pots now too. I think many of us are familiar with the sound and feel of wire wound pots. The de-greasing, deoxidizing, anti-oxidizing, and lubricating properties of "cleaners" such as they are assumed to be... or claimed to be... seem to make sense to me, for wire wound pots. For carbon film, and plastic film.... and probably ceramic film... I think de-greasing, and lubrication makes sense. Many of the pots, in the parts lists, of some Tek scopes, are specified as being manufactured by Bournes. If anyone is interested, Bournes publishes a book "The Potentiometer Handbook" in the 1970's... which is 50 years ago... but, I don't think the technology of electro-mechanical pots (like those used in old Tek scopes) has changed that much... except, I don't think they had ceramic film pots... and the build quality was much better? Anyway, pots are interesting... there are linear, log, trig, and multi-turn, as least... and the Bournes book is comprehensive. Regards. |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Just so everyone knows:
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This the understatement of the year. "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," IPA make a great paint remover -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roy Thistle Sent: Wednesday, March 06, 2019 3:17 PM To: [email protected] Subject: Re: [TekScopes] 91% Isopropyl Rubbing Alcohol to clean potentiometers? 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 |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
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 |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
Bob Albert
It looks like the link has been filtered out.? Just google the title.
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Bob On Wednesday, March 6, 2019, 11:55:07 AM PST, Bob Albert via Groups.Io <bob91343@...> 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 | | | |? |? | | | | |? | 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... | | | ? ? On Wednesday, March 6, 2019, 11:16:45 AM PST, Roy Thistle <roy.thistle@...> 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 |
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Re: 7834 with bad HV transformer free to good home
Sorry, Craig Sawyers got there first!
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David -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Roger Evans via Groups.Io Sent: 06 March 2019 20:37 To: [email protected] Subject: Re: [TekScopes] 7834 with bad HV transformer free to good home David, I have a 7934 which is in good health apart from some damage to the storage meshes at the front of the CRT, works fine in non-storage mode. I have been hoping for some time to find a good CRT from a 7834 or 7934 as a replacement. I would be delighted to come and collect. You can contact me at r.g.evans@... to minimise clutter on the list. Many thanks, Roger Evans |
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Re: 7834 with bad HV transformer free to good home
David,
I have a 7934 which is in good health apart from some damage to the storage meshes at the front of the CRT, works fine in non-storage mode. I have been hoping for some time to find a good CRT from a 7834 or 7934 as a replacement. I would be delighted to come and collect. You can contact me at r.g.evans@... to minimise clutter on the list. Many thanks, Roger Evans |
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Re: Uncooperative 7834
Before totally giving up on it, you may want to check the HV filter caps and rectifiers in the cathode circuit. I don't recall if these use the old ceramic type, or plastic caps - ones typically rated for a few kV. I've had a few of the ceramic ones go bad here and there over the years. To properly test them, besides measuring the C, you should also juice them up to a fairly high voltage, comparable to where they operate, and make sure they don't break down or leak excessively. Usually the 1500 V peak, in DC-mode, on a 576 or 577 is enough to show problems with them - if they can't handle that, then they won't make it at twice that. For testing them without doubt, they should have the full cathode voltage applied, if you have a convenient HV source.
Ed |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
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.
toggle quoted message
Show quoted text
The Most Complete Free Material Safety Data Sheet (MSDS) list of chemical information on the Internet | | | | | | | | | | | 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... | | | On Wednesday, March 6, 2019, 11:16:45 AM PST, Roy Thistle <roy.thistle@...> 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 |
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Re: 91% Isopropyl Rubbing Alcohol to clean potentiometers?
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 |
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Re: Wanted 7B15
Wait a minute Fred. At least one of those 7A29s should have the variable delay option... Still happy=;)?
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Albert On Wed, Mar 6, 2019 at 04:48 PM, Fred S. wrote:
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Re: still trying to track down 2216 manuals
Colin, thanks that was my thought also. Checked with the site nothing there. I did send him an email letting him know that Q service had a complete service manual with schematics for the 2212 on CD it is also on ebay.
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Jim O On March 6, 2019 at 3:48 AM "Colin Herbert via Groups.Io" <colingherbert@... mailto:colingherbert@... > wrote: |
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7834 with bad HV transformer free to good home
I've reached the end of my repair efforts on this 7834. I'd hoped to fix it
and sell it, but I'm not equipped to rewind the transformer and I need the space it has occupied. So if anyone in the UK wants it then they are welcome to collect it from Kenilworth. If no-one wants to take the whole thing, then I'm happy to remove boards or other parts that people want but you'll need to collect them or pay postage and packing costs. I need to have it gone within a week or so - it goes to the local recycling centre after that :( I will be keeping one piece of the metal work from the PSU as I need that for a 7854 ... unless one comes my way! PS if anyone needs CRTs for 7633 or 2564 I have to clear those out as well. David |
David C. Partridge
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