tube socket and pin connections .

I have enjoyed my ST-120 since 2012. any issues started from pin socket connections.Does anyone know What type were used in 60's free tube testers in stores when i was a kid ? what are the best made today ? I ask because when i used to ask about problems i was having voltage always came up . but i now see that a bad connection brings alot of preventable delays in the whole focus . which should be FUN !

Common "drug-store" tube testers used a variety of pin springs, mostly spring bronze - a very-near analog to phosphor-bronze with just a bit more tin (harder). Now the why?

a Drug-store Tube tester sockets seldom got hot. Enough for the tube to light and raise the meter (these were universally emissions-type testers). So, there was no danger of the springs annealing.
b) Further, any tendency to anneal would be overcome by the material's natural tendency to work-harden with use.
c) Spring Bronze has an incredible wear-factor and is highly friction-resistant. We have SB weather-stripping in our house installed in 1928 that is as resilient as the day it went in.

Typically, it was tin-plated in use.

Today, look for Phosphor Bronze springs, preferably tin-plated. It has excellent spring properties but it *will* anneal (get soft) over time from repeated heating and cooling. A few more things, while we are on sockets, tube-rolling, discontinuities, and so forth.

Those who insist on tube-rolling - a reasonable aspect of the hobby, though one that I tend to avoid (after finding a satisfactory complement of tubes in any given item) - carries easily avoided risks, sometimes discussed here. I will go through the avoidance procedures and link a bunch of tools at the end of this blather, but first.

a) Poor contact due to distortion of the pin springs. This may be avoided by re-tensioning the spring each change-of-tubes. Use a dental pick, or similar.
b) Dirt accumulated in the sockets from multiple insertions. There are miniature spiral springs that address this, but a round, fat wooden toothpick often suffices in itself.
c) Cold/broken solder joints due to wiggling from multiple insertions. Use a high-quality eutectic solder in sufficient quantity using clean wire of the correct length will eliminate this issue. I expect that few here are RoHS compliant, but even if so, this too may be accommodated.

http://cdn.kk.org.s3.amazonaws.com/cooltools/2015/06/dental-picks.jpg

https://images-na.ssl-images-amazon.com/images/I/41u2LK-Xp9L._AC_UL320_SR278,320_.jpg

http://www.kester.com/products/product/296-flux-cored-wire

http://www.kappalloy.com/eutectic-solder.php

Guys and gals, in the world of $$$$ matched pairs and quads, the cost of peripheral tools and materials that support the care and feeding of our equipment is negligible against the cost of said tubes and equipment.

And, truly, enjoyment is the key. One more platitude: the proverbial ounce of prevention is far better than the now-several pounds of cure as may be necessary.

I can't find those small brushes on Amazon. Your link goes right to a picture. What are they called?
Thanks.

https://www.widgetsupply.com/product/BER38.html?gclid=CjwKCAjwtdbLBRALEiwAm8pA5dOf29hF35EfVAaoa5CNwMSaSbL4hiG6qVfj2RQnWncO3T7qUWx1lhoCruYQAvD_BwE

Peter W. wrote:https://www.widgetsupply.com/product/BER38.html?gclid=CjwKCAjwtdbLBRALEiwAm8pA5dOf29hF35EfVAaoa5CNwMSaSbL4hiG6qVfj2RQnWncO3T7qUWx1lhoCruYQAvD_BwE  

Peter W, Thanks for the link. Just bought a set of socket-cleaners from them, shipping was more than the price, but all in, <$7. Cheaper than pipe-cleaners.
Which brings up a question that has long pestered me. When you do perform the eventual re-tension/cleaning of the socket holes, is it always wise to use De-Oxit, or is a dry cleaning sufficient?

deepee99 wrote:

Peter W. wrote:https://www.widgetsupply.com/product/BER38.html?gclid=CjwKCAjwtdbLBRALEiwAm8pA5dOf29hF35EfVAaoa5CNwMSaSbL4hiG6qVfj2RQnWncO3T7qUWx1lhoCruYQAvD_BwE  

Peter W, Thanks for the link. Just bought a set of socket-cleaners from them, shipping was more than the price, but all in, <$7. Cheaper than pipe-cleaners.
Which brings up a question that has long pestered me. When you do perform the eventual re-tension/cleaning of the socket holes, is it always wise to use De-Oxit, or is a dry cleaning sufficient?

For the record, I do not and will never use DeOxit as a brand. Their corporate ethics leave much to be desired, although their product, while vastly overpriced, is excellent. That cannot be taken away from them.

I find that solvent-cleaning is generally unnecessary, and if over-done can be dangerous. The first time the sockets are cleaned, perhaps. But if the springs are tight, the friction of insertion should be enough to insure contact. I keep an electric eraser for cleaning tube pins - so I can insure 'shine' there as well. NOTE: These electric erasers are excellent for gentle cleaning of many sorts of devices, the problem with them is finding the eraser inserts. I am blessed to have found a lifetime supply of same at an art-supply store, and bought them all at actual retail. Now, a single insert can go for $10 or more.

https://www.artsuppliesonline.com/prodimg/6150.jpg

I find it encouraging that one more person refuses some companies products on the basis of ethics.
And in addition freely talks about it! Thanks for this, it's exactly how consumer influence works.

peterh wrote:I find it encouraging that one more person refuses some companies products on the basis of ethics.
And in addition freely talks about it!  Thanks for this, it's exactly how consumer influence works.

Actually, I find that 90+grade denatured alcohol cleans most anything just fine. I use it on my tape-heads. The lower grade grocery-store varieties are diluted with oils which are unhelpful for our purposes.

Peter W. wrote:https://www.widgetsupply.com/product/BER38.html?gclid=CjwKCAjwtdbLBRALEiwAm8pA5dOf29hF35EfVAaoa5CNwMSaSbL4hiG6qVfj2RQnWncO3T7qUWx1lhoCruYQAvD_BwE

deepee99 wrote:Peter W, Thanks for the link. Just bought a set of socket-cleaners from them, shipping was more than the price, but all in, <$7. Cheaper than pipe-cleaners.

I use Equate Interdental Brush Cleaners.  $3.86 for 20 at your local Wal*Mart toothpaste aisle.  Perfect size for 7 & 9-pin sockets on up. One brush can clean many sockets before wearing out.

deepee99 wrote:Which brings up a question that has long pestered me. When you do perform the eventual re-tension/cleaning of the socket holes, is it always wise to use De-Oxit, or is a dry cleaning sufficient?

91% isopropyl alcohol gets all the atmospheric deposits off; I'm still using my old bottle of Cramolin Red from the 1970s to get off oxidation/corrosion, diluted 1/10 with denatured alcohol.

Just my $0.02.

Lately, I had pin contact issues with my right front power tube in ST-120. It too was built in 2012. The filaments do not light up when cold but I measure 6.6Vac on pins 2-7. I swabbed the pins with TechSpray and a pipe cleaner. Afterward the end of the pipe cleaner was visibly dirty.

So pin maintenance will be an issue going forward. Cleaning and retensioning pins will be done more frequently. And will be looking at the smaller brushes mentioned above.

Another cheap grocery-store option is Mr. Clean Magic Eraser
https://www.target.com/p/mr-clean-magic-eraser-cleaning-sponge-2ct/-/A-50790981?ref=tgt_adv_XS000000&AFID=google_pla_df&CPNG=PLA_Grocery+Essentials+Shopping&adgroup=SC_Grocery&LID=700000001170770pgs&network=g&device=c&location=9029666&gclid=EAIaIQobChMItrjg1d7C1QIVTl9-Ch3dgwUSEAYYBCABEgIOWPD_BwE&gclsrc=aw.ds
I've never used it with water, but just dry it will put a nice clean shine on tube pins.
Coupla bucks will get you a lifetime supply.

I'd be fascinated to get some more info on the offending "corporate ethic" of which you speak ... I imagine you could find some dirt on any mfg in the market nowadays ...

sKiZo wrote:I'd be fascinated to get some more info on the offending "corporate ethic" of which you speak ... I imagine you could find some dirt on any mfg in the market nowadays ...

Effectively Caig adapted the formula for DeOxit from Cramolin. Cramolin is a German company, still active, that used Caig as their US distributor for many years. At some point, Caig stopped being the distributor, and DeOxit line was born. There is much more out there - one rather balanced explanation is linked below. Searches will reveal unbalanced reports as well.

http://www.pitt.edu/~szekeres/caigcram.htm

Peter W. wrote:
Effectively Caig adapted the formula for DeOxit from Cramolin. Cramolin is a German company, still active, that used Caig as their US distributor for many years. At some point, Caig stopped being the distributor, and DeOxit line was born. There is much more out there - one rather balanced explanation is linked below. Searches will reveal unbalanced reports as well.

http://www.pitt.edu/~szekeres/caigcram.htm  

Huh, never knew all this. Hard to draw conclusions though with internet data, there's always "the rest of the story..."

Huh, never knew all this. Hard to draw conclusions though with internet data, there's always "the rest of the story..."[/quote]

The bad blood between the two companies is very real.

When I was working overseas, I still pursued my hobby, and had occasion to purchase Cramolin products in the electronics souks. One of the requirements was that any product for local sale had to be labeled in English and Arabic to include the complete contents - no 'proprietary ingredients'. Cramolin ContactClean was labeled as follows:

Hydrocarbons and hydrocarbon propellants including Propane and Naptha: 95%
Oleic Acid: 5%.

Caig products are not sold in Saudi. If I wanted such, I would have had to go to the Radio Shack in Bahrain.

http://www.conrad.com/ce/en/product/820531/Electrical-contact-cleaner-Cramolin-CONTACLEAN-1011611?ref=list

This can was SR15, about $4.

Is there anything De-Oxit or its equivalents can do that 90+% oil-free denatured alcohol can't?
I know Roy M. recommends a good rub-down of the circuit-boards with high-test denatured alcohol in his pre-amp kits before starting assembly.

deepee99 wrote:Is there anything De-Oxit or its equivalents can do that 90+% oil-free denatured alcohol can't?
I know Roy M. recommends a good rub-down of the circuit-boards with high-test denatured alcohol in his pre-amp kits before starting assembly.

Denatured alcohol comes in several 'flavors', so be cautious about the amount of methanol in the mix. This stuff can craze some plastics. The stuff I have used with success has been 93.5/6.5 Ethanol/Isopropyl. Some can have as much as 6% methanol in the mix.

Peter W. wrote:

deepee99 wrote:Is there anything De-Oxit or its equivalents can do that 90+% oil-free denatured alcohol can't?
I know Roy M. recommends a good rub-down of the circuit-boards with high-test denatured alcohol in his pre-amp kits before starting assembly.

Denatured alcohol comes in several 'flavors', so be cautious about the amount of methanol in the mix. This stuff can craze some plastics. The stuff I have used with success has been 93.5/6.5 Ethanol/Isopropyl.   Some can have as much as 6% methanol in the mix.

Learned that lesson about methanol the hard way. It will turn the pinch-rollers on a very expensive tape-deck pear-shaped in a hurry, so, yes, ethanol/iso it is.

deepee99 wrote:Is there anything De-Oxit or its equivalents can do that 90+% oil-free denatured alcohol can't?
I know Roy M. recommends a good rub-down of the circuit-boards with high-test denatured alcohol in his pre-amp kits before starting assembly.

I don't know how well DeoxIT removes airborne contaminants (tobacco and other smoke deposits in old audio gear tube sockets, primarily) or spilled alcoholic beverage residue (guitar amps) but 99% ethanol will get it outta there.  DeoxIT then removes old oxidation, and (AFAIK) leaves a bit of lubricant behind that reduces future oxidation.

I use the previously mentioned dental brushes because they DON'T have metal bristles that excoriate the socket contacts, but DO provide a bit of mechanical agitation that gets contaminants and oxidation out of the sockets.

Anyway, that's my protocol for repair/maintenance for old audio gear I get on my bench.

One thing about De-Oxit is that it is highly flammable (most solvents are).
Tried it out on a dodgy mogul light-bulb socket one time, screwed the 200-watt bulb back in and hit the switch. Smoke spewed instantly. Damn near burned the house down, so don't ever use it on a hot component.

Let me add to the last two posts above this one...

De-Oxit D5 spray is 75% naptha which functions as a carrier for the 5% remaining ingredients and the 20% carrier. It also has significant cleaning properties (naptha = white gas) and will dissolve tars, nicotine, and other smoking deposits along with similar contamination; it then flushes the removed contaminants away. That's one more reason the naptha is very useful - as a flushing agent.

Naptha does not evaporate as fast as some other solvents which is useful in the cleaning process. However is does mean you need to be careful not to expose anything it was used on to an ignition source until the naptha carrier is completely evaporated - otherwise you get the display that David got with his bulb! Quoting Caig's instructions:

"Formulation contains petroleum naphtha (odorless mineral spirits) solvent, and is briefly flammable (until solvent evaporates within 2-3 minutes). It’s slower to evaporate, providing flushing action to remove surfaces dirt, grease and other contaminants."

I have excellent success with the product - just follow the instructions!

Jim McShane wrote:Let me add to the last two posts above this one...

De-Oxit D5 spray is 75% naptha which functions as a carrier for the 5% remaining ingredients and the 20% carrier. It also has significant cleaning properties (naptha = white gas) and will dissolve tars, nicotine, and other smoking deposits along with similar contamination; it then flushes the removed contaminants away. That's one more reason the naptha is very useful - as a flushing agent.

Naptha does not evaporate as fast as some other solvents which is useful in the cleaning process. However is does mean you need to be careful not to expose anything it was used on to an ignition source until the naptha carrier is completely evaporated - otherwise you get the display that David got with his bulb! Quoting Caig's instructions:

"Formulation contains petroleum naphtha (odorless mineral spirits) solvent, and is briefly flammable (until solvent evaporates within 2-3 minutes). It’s slower to evaporate, providing flushing action to remove surfaces dirt, grease and other contaminants."

I have excellent success with the product - just follow the instructions!

"Just follow the instructions?" Now there's a concept I've never tried, Jim.

... instructions are for wimps.

deepee99 wrote:Is there anything De-Oxit or its equivalents can do that 90+% oil-free denatured alcohol can't?
I know Roy M. recommends a good rub-down of the circuit-boards with high-test denatured alcohol in his pre-amp kits before starting assembly.

Oleic acid attacks products of corrosion and oxides on copper, silver and brass (zinc & copper) as well as bronze (tin & copper) and has been used for cleaning brass clock movements for many years. Alcohol is a very mild alkaline and so can also interact with various oxides, but not as quickly or surely as Oleic acid.

On the other hand, too much Oleic acid can continue to react even with fresh metal, with bad results.

So, cutting to the chase: If there are corrosion products to be removed, something more active than alcohol is needed. If all we have is skunge, (technical term), oils, nicotine, bacon-grease and the like, alcohol is both sufficient and best. And a soft, worn-out toothbrush.