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 Post subject: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 3:48 am 
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Joined: Jan Mon 16, 2017 3:08 am
Posts: 159
Location: Boise, Idaho
I was reading an old thread from 2011 on restoration of a 410B and a poster said they:

Wash with a mix of 70/30 709/household ammonia

Followed by 99% iso alcohol.

I started using "Super HFE Electronics Cleaner" but at 27 bucks a can I sure would like to know that ammonia mix/ concoction is. Anyone know? I am thinking I may try it on some wafer switches I screwed up using Deoxit before I knew better.


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 7:38 am 
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Joined: Sep Sat 27, 2014 4:24 am
Posts: 1375
Location: Oxford, MI
709 is a type of cleaner sold in spray bottles around here, don't know if they sell it by you.

The OP is suggesting to mix it 70% 709 cleaner with 30% ammonia. I have no experience with this but would clarify the mix.

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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 1:25 pm 
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Joined: Jan Mon 16, 2017 3:08 am
Posts: 159
Location: Boise, Idaho
409 yes, 709...never heard of it. Google brings up brake cleaners such as ST 709 for results for "709 cleaner" search.


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 3:34 pm 
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Location: Oxford, MI
http://www.karnakcorp.com/images/PDF/709.pdf

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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 3:43 pm 
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Location: Boise, Idaho
Thank you. Asphalt and Tar remover/ roofing products. I never would have come up with that one.


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 3:56 pm 
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I don't think this is the kind of cleaner you want to use on switches and pots, I would stick with alcohol or similar. This sounds more like a general chassis cleaner/degreaser.

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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 4:05 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 11544
Location: S. Dartmouth MA 02748-1225 USA
For cleaning contaminated tube tester switches some tester gurus have used 91% to 100% isopropanol alcohol. Available at drug discounters for about $2.50/qt. Dousing and effective scrubbing with an "acid" brush, rinsing (picking out brush bristles) and drying with compressed air until the wafers have warmed. The alcohol and compressed air will cause the switch to lower temperature below dew point and condense moisture, not good. Or follow-up with heat gun. Careful examination of all contact blades to be sure they open when wiper passes. Lubricate only the shaft and ball detent mechanism.

Any formula that may leave a residue could cause leakage in certain high impedance circuits when testing a tube.

Chas


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 5:33 pm 
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Joined: Jan Mon 16, 2017 3:08 am
Posts: 159
Location: Boise, Idaho
Hcompton79 wrote:
I don't think this is the kind of cleaner you want to use on switches and pots, I would stick with alcohol or similar. This sounds more like a general chassis cleaner/degreaser.


https://groups.yahoo.com/neo/groups/hp_ ... ages/36792

A rather interesting (or not) discussion ensued over iso alcohol.


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 6:11 pm 
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Joined: Apr Tue 11, 2017 8:38 pm
Posts: 13
Gibson wrote:
Hcompton79 wrote:
I don't think this is the kind of cleaner you want to use on switches and pots, I would stick with alcohol or similar. This sounds more like a general chassis cleaner/degreaser.


https://groups.yahoo.com/neo/groups/hp_ ... ages/36792

A rather interesting (or not) discussion ensued over iso alcohol.


There's a lot of confusion in that thread about isopropanol alcohol sold in drug stores (not generally denatured, it's already inedible) and ethyl alcohol sold in drug stores (denatured with all sorts of things which you might not want on electronics -- acetone, bitterants, etc). Ironically while the hardware store denatured alcohol is more toxic to humans (I think it's typically 90/10 ethyl/methyl), I believe it's a mixture that evaporates completely. Not sure I'd trust it for "sensitive" cleaning though.

MG chemicals makes a 99% isopropanol spray can. Its kind of pricey, but really nice when you don't know whether lubricant residues from a conventional contact cleaner will cause problems or you want to just blast the crud off of everything. I successfully cleaned up the rotary encoder contacts in a modern (well, 20 year old) oscilloscope this way and didn't need to worry about getting it all over the front panel PC board.


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 Post subject: Re: Homebrew Cleaning Concoction
PostPosted: Apr Thu 20, 2017 7:37 pm 
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Joined: Jan Mon 16, 2017 3:08 am
Posts: 159
Location: Boise, Idaho
mmagin wrote:
Gibson wrote:
Hcompton79 wrote:
I don't think this is the kind of cleaner you want to use on switches and pots, I would stick with alcohol or similar. This sounds more like a general chassis cleaner/degreaser.


https://groups.yahoo.com/neo/groups/hp_ ... ages/36792

A rather interesting (or not) discussion ensued over iso alcohol.


There's a lot of confusion in that thread about isopropanol alcohol sold in drug stores (not generally denatured, it's already inedible) and ethyl alcohol sold in drug stores (denatured with all sorts of things which you might not want on electronics -- acetone, bitterants, etc). Ironically while the hardware store denatured alcohol is more toxic to humans (I think it's typically 90/10 ethyl/methyl), I believe it's a mixture that evaporates completely. Not sure I'd trust it for "sensitive" cleaning though.

MG chemicals makes a 99% isopropanol spray can. Its kind of pricey, but really nice when you don't know whether lubricant residues from a conventional contact cleaner will cause problems or you want to just blast the crud off of everything. I successfully cleaned up the rotary encoder contacts in a modern (well, 20 year old) oscilloscope this way and didn't need to worry about getting it all over the front panel PC board.


As of recently, I have been using the MG Chemicals Super HFE on two 410B's I am working on. I am fairly convinced I have issues with a 98A that I sprayed down with Deoxit after receiving bad, or malicious advice. Again, at 27 bucks a can I hate to use it as a flushing agent on the 98A but instead continue to use it in terms of precision spot cleaning. As far as the MG Chemicals 99.9% iso, it might be worth the price of admission in certain applications; at least you know what your getting. I am getting old and don't have the time left on this earth to learn chemistry.


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