The Dreaded Switching Jack Problem

[The Dude]

For CLiff-type jacks, I have used a 1/8" burnisher for decades, it works like a charm.

Mine is a GC9337, made by GC.

FRYS.com*|*GC Thorsen

There are also wider ones.


Back when I worked on relay systems we used burnishing tools a LOT.

I use one of those, too! It's still in the original little red plastic holder.

[Enzo]

Mine too. I have a small cardboard box in the corner of my tool cart drawer, it holds small hand tools. Looking for that red plastic cover is how I find the thing.

It is the perfect size to fit into the Cliff jack contact spaces.

[km6xz]

This thread has been up for a long time and just read it for the first time. I am surprised that oxidation surprised so many people. I am also surprised so many people use abrasives on plated contacts. Burnishing tools are for soft contacts like heavy relays, power contactors etc, not for plated contacts which only need a bit of chemical de-oxidizing that does not score the hard plating at all.
Scored contacts will have higher resistance and will corrode much faster.
Oxidation is not dirt, it is the natural result of most metals in a sea of atmospheric oxygen and is a good thing....in moderation. A thin layer of oxide of the base metal is an insulator and pretty inert so more serious deep corrosion is prevented. Every melt aluminum? It is by nature, bright like mercury but is highly reactive with oxygen and corroded very quickly with a layer of aluminum oxide that protects the surface from more corrosion. It is the dull grey coating on aluminum, and of course our electronics depends on oxides such with semiconductors, electrolytic caps etc. High value caps indicate just how good an insulator oxide is, the oxide layer is very thin.

Any normaled contacts will oxidize eventually, many pots and linear faders will also even if the main resist is plastic or carbon film. Every jack bay will be a potential intermittent or distortion inducing connection, it is a fact of life and every tech should be aware of preventative maintenance routines and schedules. Recording studios has thousands of TT jacks in each control room, and every patch cord. So, once every 6 months or so, every jack bay and every patch cord is treated with a very thin wiping of some form of deoxidizing chemical. It is not cleaning(cleaning with solvents increases oxidation), it is a chemical reaction that required extremely small amounts, just enough to slightly wet the surface. Any more, is usually wasted.
Pay attention to the solvents used in cleaning equipment and know what material the plastic parts are made of before choosing a cleaner. Some plastics react badly, by melting or shattering is contacted by the wrong solvents. Keep solvents out of jacks, pots and connectors, and do not use "Contact Cleaner" on contacts, it is too "dry", dries too completely leaving the surface much more likely to corrode much quicker than if left alone. If you use a solvent cleaner, do not get it on contacts that have just been deoxidized or you have just undone your own work. Get a syringe and apply deoxidizer lightly directly on the resist surface of pots, and do not use spray. That uses too much, mostly gets on the pot lubricant so the pot feels bad to the touch with its shaft lube washed out. Same with the slides of linear faders, a fine fader can be turned to junk with one squirt of solvent or de-oxidizer.

Anyway, what were techs doing if they got the symptoms of intermittent distortion or signal loss before being told of normalizing contacts in inserts and loops? The type of distortion generated and the weak signal symptoms should narrow the range of probable causes dramatically.

[Brazen]

... and "dissimilar metals" cause a lot of the oxidation issues in electronics.

DeOxit is a "Gadget Guy's" best friend! lol

[guitician]

Wirewound pots and gold plating..... design it well and eliminate the problem.

[Wes]

Big Orange Box Store and many electrical warehouses sell this:




It's about 3$ for the shorty can. It's comparable to deoxit at a quarter of the price.

[g1]

Looks like it's just a lube, not also a cleaner like de-oxit?

[Enzo]

Yep, just a lubricant, not5 a deoxidizer and contact surface preparation.

[Wes]

That in conjunction with contact cleaner has always worked for me. I don't use that stuff on jacks or sockets.

[TimmyP1955]

Silver oxidizes.

"Silver oxide is very conductive."

Maybe in the lab, but not in the real world when the current levels are very low.

I had to pitch some NOS silver switches as the solder tabs got so bad that they would not take solder. I filed down to the base brass and it would not take solder either. This was unusual, but still...

[Maxrocks]

Hi Jazz P Bass, thank you for the info, now that I see how easy the unit comes apart, I will try using a jack to try and clean it out, now I just replaying again and it worked from I will say a while back, after my wife moved it, that is when it stopped working, light comes on...................I tried to open the PDF file but got a blank page. I must to all it is a pleasure meeting true musicians with so much knowledge

[Jazz P Bass]

I tried to open the PDF file but got a blank page.

Here is the 'Jack' file.

http://music-electronics-forum.com/a...ck-problem.pdf

(The first link is dead. If you toggle down to a newer post, I reloaded the pdf. file.)

[Usable Thought]

Here is a copy of an awesome article about switching jacks.

PDF link downloads a transparent GIF, nothing else. Original copy of article has some problem also on the Preston Electronics site - there is a web page but it doesn't open properly and all the graphics are missing.

[DRH1958]

Here it is in PDF. Pretty sure this it all of it : The Dreaded Switching Jack Problem.pdf