Assuming not sputter damaged contacts, otherwise good underlying surfaces. I use a nylon cable tie, introduced with the contacts in contact. In a filing action with the ratchet part of the nylon, then turn upside down and repeat
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
I get the impression that you are talking about pin and socket connectors rather than 'button' contacts as used in relays for example. First of all, connectors have a very finite numbers of mate-unmate cycles in their original design and once they reach that number [either half] they are basically scrap. Further, if you mate a worn out connector with a good one, you may contaminate the surface of the 'good' half and compromise it's future performance. Except for connectors especially designed for large numbers of mating, most commercial connectors are good for 50 to 200 cycles, and that is highly dependent on the environmental conditions [dust and grit are a quick death]. Once the surface plating is worn through or the pins have overheated and lost some spring tension, there is nothing one can do to improve the connection but replace it with NEW components.
Best replacement? Depends on the application. A lot of engineering goes into the choice of a simple connector for a product if long life and durability are needed.
The OP didn't say a whole lot. Some oxides can be removed with water, like the green type. Not many contact cleaners actually remove oxide. Oleic acid based cleaners will help remove oxides as well as friction.
The original Caig Cramolin (red) works well on tin and nickel surfaces. ProGold does a fairly good job on gold surfaces. Go to the Caig site and see what you think. Try not to be too alarmed at the high prices. (These are "professional" (not consumer) products, and Caig gouges.)
There are probably other effective products out there.
I get the impression that you are talking about pin and socket connectors rather than 'button' contacts as used in relays for example. First of all, connectors have a very finite numbers of mate-unmate cycles in their original design and once they reach that number [either half] they are basically scrap. Further, if you mate a worn out connector with a good one, you may contaminate the surface of the 'good' half and compromise it's future performance. Except for connectors especially designed for large numbers of mating, most commercial connectors are good for 50 to 200 cycles, and that is highly dependent on the environmental conditions [dust and grit are a quick death].
Neil S.
That seems a bit pessimistic. I have many lead sets in my workshop - phono, jack, XLR, Speakon, SCART etc - which have been made up using fairly 'bog-standard' connectors from the likes of Maplin, Farnell etc, or bought ready made from the same sources, and these are used several times, just about every day, to connect up items that are in for repair. Many have been in use for years. Musical instruments are jacked into amplifiers and mixer desks many many more times than 200 in their life, and most such items employ very 'standard' and inexpensive makes and designs of jacks and plugs. I think that I would be pretty disappointed with *any* connector in a user application, no matter how cheap and nasty it was, that was considered shagged out after as little as 200 uses.
That's an awfully small number. A properly manufactured gold-plated connector should be good for at least 10 times that, shouldn't it?
I'm pretty certain the sorts of connectors used on (say) flash RAM are good for a couple thousand cycles. They'd have to be (???), as it's assumed the card will be repeatedly inserted and removed.
For brass 316 jack plugs, use a green nylon scouring pad.
If the corrosion is on battery connectors that have been used with alkaline batteries, you will wreck the surface with dry physical cleaning before you make contact - but with a drop of water, the corrosion comes off easily.
--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
If you have logic levels in mind, and some noise margin, a slightly dirty connector is no big issue. Some RF test equipment, though, has to be concerned with milliohms of resistance, and can be completely defeated by a small amount of oxide (like, a copper oxide rectifier making harmonics out of your main signal, or a mechanical vibration sensitivity - the avionics guys hate that).
So, commercial connectors that are 'good' for 200 cycles are possibly adequate for 10,000. There's a few critical applications where connector insertions are counted and connector-replace is performed at suitable intervals.
:Have been Googling the proper way to clean plated electrical contacts :but either get nothing if use " or a lot of nonrelevant hits without. : :Am interested in any suggestions esp how to remove the nonconductive :oxides. : :If a connector is too damaged would also be interested in what are :considered the best type replacement. : :Thanks : :Gene
I don't think I have ever come across a "plated" electrical contact. In my experience electrical contacts are always a solid material such as brass (cheap and nasty - often used in electrical appliances) or a more exotic alloy material such as nickel-silver. The contact material used is dependant on the application (AC or DC and whether inductive) and the magnitude of the current being handled.
Most relay contacts can be cleaned and reconditioned using a contact burnishing tool such as
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The use of a lubricant such as those mentioned in other responses may be considered useful.
I'm sure that you must have, Ross ?? I'd agree with you on 'solid brass contacts' in clunky mains power switches etc, but elsewhere, many contacts seem to be plated rather than solid. For instance, I just put the word "plated" into the search pane on one component supplier's website, and it came back with 59 items, most of which were connectors with a variety of plating materials quoted for their contacts, including gold, silver & tin. Similarly, a quick look in a catalogue at switches, reveals many to have either gold or silver plated contacts. Also, many relays have contacts described variously as gold "plated", "covered", "overlayed" etc. It is these contacts that I find you have to be careful not to use any kind of abrasion on, for fear of going through the very thin layer of plating. I generally find that pulling a piece of dry cardboard through things like relay contacts, is enough to clean them. A tiny spot of cleaner/lubricant introduced to the contact gap, finishes the job off.
I have had very good luck repairing low current relay contacts and mechanical rotary switches using "tarn-x" silver cleaner containing acidified thiourea. MSDS:
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If you take the relay or switch apart to get to the contacts, use a cotton swab with a small amount of cleaner and apply to the oxidized (tarnished) surfaces. They shine right up and the surface does not appear to be damaged by it. Then dry and apply a very light film of silicone based contact cleaner to keep the air away and help with lubrication. Works great for speaker relays in amplifiers and mode switches for VCR's.
Silicone based products are really not a good thing, at least thats what some say. However sometimes a silicone grease is used to protect connections. Silicone sprays were common 30 years ago. I don't recall any of the more common recommended sprays having silicone. I see mixed recommendations of lubing relays. Some say no, but I do.
Silicone based cleaners leave a residue that protects against friction but tends to insulate. You have to break through the film in order to even have contact. I have found them useful for connectors that see lots of use, such as Notebooks, but I usually have to wash them with Isopropyl to remove most of what I put on.
There is no point in lubing relays. Any residue will increase the likelihood of burning of the contacts. They should be cleaned and burnished with a non-residue cleaner and as minimally abrasive tool as possible. Bond paper strips will often suffice.
Isopropyl Alcohol at 90% or better is clean, leaves no residue, won't harm most plastics and is the only recommended cleaner for many switches and contacts. Do not use less than 90% as there will be risk of moisture damage.
I got some of that stuff. For rubber and some plastics petroleum based products can hurt. I have been using plastic safe liquid CRC 2-26 but I really don't know whats in it. For those outside the US, if you use Cramolin Contaclean, it must be removed after cleaning because it will gum. Here is an old can. Check out the buildup at the top.
I kind of like using 70% rubbing alcohol sometimes, with its small amount of mineral oil. Any % alcohol can cause moisture problems, even 100%. The trick is to warm dry it.
My knowledge of silicon is it forms waterglass in some cases and insulates. This is a powder like material. Sodium silicate. It does wash off.
I also discovered thick sticky residue on my can of CRC 2-26, but its a more passive lube than the acedic nature of Cramolin Contaclean. My can of TAL-5 is also sticky, was made by WD-40 company. From memory I have never seen this happen with WD-40.
snipped-for-privacy@zekfrivolous.com (GregS) wrote in news:h987mf$4bh$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:
contact wiping pressure should handle that "insulating" film. Only TEK "HF switch contacts" didn't have enough wiping pressure to deal with films left from tuner cleaner/lube sprays.
I used to use Tarn-X on TEK 500 series tube scope rotary switches,to clean off the black oxidation. It worked great,had to wash and oven-dry the scopes anyways. You must RINSE the contacts after using Tarn-X on them.
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