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
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
http://home.graffiti.net/diverse:graffiti.net/
> Am interested in any suggestions esp how to remove the nonconductive
> oxides.
A good contact cleaner followed by a switch lubricant - will help prevent
corrosion later. Servisol or Electrolube for the latter.
> If a connector is too damaged would also be interested in what are
> considered the best type replacement.
--
*The modem is the message *
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
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.
Neil S.
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.
greg
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.
Arfa
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)
www.poppyrecords.co.uk
> That's an awfully small number. A properly manufactured gold-plated
> connector should be good for at least 10 times that, shouldn't it?
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
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 http://www.mcmelectronics.com/product/22-910
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.
Arfa
I have had very good luck repairing low current relay contacts and
mechanical rotary switches using "tarn-x" silver cleaner containing
acidified thiourea. MSDS: http://www.jelmar.com/msds/TX_MSDS_eng.pdf.
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.
Scott
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.
greg
Silicone based chemicals were banned from all telephone switching
centers with mechanical switching.
The old General Cement "Tuner Lube" is petroleum based and doesn't
build up an insulating film like Silicone based products.
--
You can't have a sense of humor, if you have no sense!
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.
http://zekfrivolous.com/misc/cramolin%20contaclean.JPG
greg
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 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.
greg
The vast majority of connectors which aren't plain brass are plated.
--
*When cheese gets it's picture taken, what does it say?
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 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.
>
> http://zekfrivolous.com/misc/cramolin%20contaclean.JPG
>
> greg
>
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.
--
Jim Yanik
jyanik
at
kua.net
Rubbing alcohol shouldn't have any mineral oil in it.
I prefer 90% isopropyl.It also absorbs any water or moisture.
Some has 'Oil of Wintergreen' but that is usually colored green. It
is an old type of pain killer. They still make it, but they don't use
real 'Oil of Wintergreen'. between the dye and other additives, I
wouldn't use it on electronics. I do use it for some types of pain in
my hands, from the Diabetic Neuropathy.
Been there. I love big silver plated ceramic switches.
A friend used to say, he liked using both Cramolin Red
and Tweek on contacts, together.
The current Caig R100 full strength is also great.
greg
The reason there is oil in some, its supposed to give oil
back to the skin after a rub down. After using alcohol on the skin its usually
very patchy looking removing the oils.
I didn't exactly point out, even using 100% alcohol on
things, and you will get water build up, after the alcohol
starts absorbing it, and dries, leaving water. Plus, 100%
is contaminated with drying agents.
greg
You will get dry patches of blue.
I got an experiance I never felt. I eat hot peppers all the time,
and have heard of capsation rub for pain. Capsation particles
are extremely small and float in the air.
Well, I was cleaning some Habenero and jalape�o
peppers in haste scraping the seeds out and taking most
of the core. Besides having to wash hands many times and
being carefull, after about 20 minuites I started to feel the action
penetrating the skin on my hands. They were tingly,
much the same as a burn would do but mild. It
wasn't a real bad feeling, but I could see how it might numb
pain in the joints.
Also try vitamin D. If your out in the sun, forget it. Just take minerals.
1000-2000 units D-3.
greg
Years ago, we used to treat the long multipole open slide switches that were
fitted to dual standard TV sets, to a liberal does of white heatsink paste.
This did a grand job of stopping the sections that did the timebase
switching, from arcing, and the sections that did the low-level signal
switching, from tarnishing and becoming intermittent. Happy days. Gentler
times ...
Arfa
:
:"Ross Herbert" <rher...@bigpond.net.au> wrote in message
:
My experience has been mainly related to relays of both open and enclosed types,
from miniature pcb mounted types for signal transmission to heavy duty high
current capacity types. I will agree that particularly for the low level signal
types the manufacturers often "enhance" the contact material by adding a gold
"overlay". However, the actual relay contact will be made of some alloy material
such as silver-palladium or other mixture. The contact is usually rivetted or
welded to the spring leaf, which is probably a plated phosphor bronze material,
while the gold overlay on the contact pips is simply to reduce contact
resistance due to oxidation through lack of a wetting current. A typical relay
of this type, which I have on hand, is the Fujitsu FBR46. With such relays, as
you have mentioned, you never use abrasive methods of cleaning or burnishing but
with gold as an overlay this should not be necessary. The problem with any
"plated" contact is that once the plating material has been lost either through
repeated operation or arcing etc, the base contact material is all that is left.
In cases where no plating is used unless the contact material is one of the
recognised traditional materials such as nickel-silver, silver-palladium etc,
the electrical performance of the contact will be unreliable. Such a relay used
for heavy current carrying capacity which I also have on hand is a Fuji HH62
witha contact rating at 10A. In this case the contact material is simply a
"silver alloy" - probably made to Fuji specification. Such contacts can be
burnished and reconditioned using abrasive tools.
It may be that later contacts, manufactured for cheapness, do not use
traditional solid alloy contact material which is rivetted or welded to the base
contact spring material, and by so doing they would, in my opinion, be inferior
to the types which do.
Your blockquoting looks pretty sad.
http://groups.google.com/group/sci.electronics.repair/msg/c89433e3d6dba496?dmode=source
Have you heard of this 3rd-party update for your M$ software?
http://google.com/search?q=inurl:jain+%22+OE.doesn't.exactly.feature.the.most.intelligent.quoting.algorithm
Funnily enough, as soon as I replied to that particular post, I thought it
looked 'wrong' ... To be fair, I don't usually quote in a way that appears
"sad" or confused as far as I am aware. When my replies pop up in threads,
they usually seem to look ok on my machine. However, thanks for the pointer
to that piece of software. I've put it on now, so perhaps that will allow my
posts to present in a way that does not further upset your sensibilities ...
I'm sure you'll let me know if that's not the case ?? :-)
Arfa
OK. Understand what you're saying ...
Arfa
This looks much better. Often text you cited from previous posts appeared inline
as if it were your original material ;)
Michael
Interesting that you say "often". I really hadn't noticed that this occured
except on the odd occasion, and I had always put that down to there being
something amiss in the formatting of the text that I was 'breaking into'
with my comments. I don't very often reply in that way, answering individual
points within the text body of the original post. Normally, I append a total
reply to the bottom of the post, sometimes snipping irrelevant text from
above or below, if it is one specific point that I am replying to, or where
the post has become unnecessarily rambling. I had always thought that the
original text gained right arrows at the start of each line automatically,
with my text identified by not having these, as a function of OE as it
stands, and when these didn't appear, as was the case that started this
sub-discussion, that something had just 'gone wrong'. Surely, I wasn't
seeing something different on my machine, than what everyone else was
seeing, was I ? Presumably, once the post is on the server, I see the same
as everyone else, don't I, even though it's my own post that I'm looking at
?
I must admit to being a little confused now (not unusual !) The indicated
bit of software is now installed, and I guess it must be doing something as
you say that things now look "better", but I'm not sure exactly what I am
seeing here, that looks any different, other than the number of right arrows
at each line start seems to be increasing as you go further back ... ??
Arfa
That's what its supposed to look like. Each new meassage is supposed
to add another row of arrows to any quoted text, so you can tell who
posted what without going back and reading every message in a thread.
> I must admit to being a little confused now
FWIW I don't remember your posts having a quoting problem before.
But I'm confused, too: I don't understand why so many people use an
operating system that has to be patched every three days, and software
that has to have third party shit added to it to work properly.
Fair enough ! Mission accomplished then, I guess ...
Arfa
Well, part of it is that I don't look good with a beard, or in sandals. I
also find riding a bike a bit too much like hard work ... :-)
Seriously though. My computers are just tools. They are not a hobby where I
like to tinker with software and so on. I understand probably more than most
average Joes about how they work, and how to keep them working, but the
vagaries of operating systems and so on, are way, waaaayy over my head. For
that reason alone, I just leave them with the Windows OS on them that they
came with, but as a side issue, I like to know that if I buy or download a
piece of software, chances are it can be thrown onto the machine, and will
just work with a minimum of fuss.
Gates-bashing seems to be an international pastime, and one that I don't
really understand. OK, so the guy makes a lot of money, and some of his
company's policies might be a bit monopolistic, but so what ? He puts a lot
back into the community, and I really don't think that his business
practices are any worse than many other large corporations. It also has to
be remembered that pretty much single-handedly, that company has been
responsible for spreading affordable and powerful computing throughout the
world, from the poorest to the richest countries, and with a common platform
that allows anyone from any of those countries, to develop software that can
be used by pretty much anyone *with* a computer.
As to it needing patches every couple of months, it has to be remembered
that it is a large and complex piece of software, trying to please all of
the people, all of the time. Of course there are going to be bugs, and as we
all know, patching one - in any piece of software let alone an OS - is
likely to cause other problems that just can't be forseen until they occur.
Many of the patches are security-related, and wouldn't be necessary if the
little toe rags who think it's funny to attack computers and wreak havoc in
the commercial world, were properly targetted, and jumped on from a great
height. Anyway, updating with those patches is no great shakes, is it ? My
Windows machines check with MS regularly, and just get on with downloading
and installing any updates, with little intervention from me.
And before everyone starts squawking at me in self-rightous indignation for
being crass enough to use, and actually *like* Windows, I really don't care.
It does what I need it to do, without me having any deep understanding of
either it, or the computers it runs on, and does it pretty much faultlessly
the majority of the time ... d;~}
Arfa
I use the ink (ie; rougher) end of an ordinary eraser.
--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------