I just like to give the readers an option. For transmission line terms,
they can choose between HP/Agilent's usages and definitions, or yours.
For terminology regarding contacts, they have their choice between 3M's
and Richard's. And for engineering educational standards, readers can
choose among Ronold King, Terman, and Kraus, or Reg Edwards. I'm sure
each will make the choice that he/she feels most confident with.

Roy Lewallen, W7EL

Reg Edwards wrote:
It's an "abuse of language" shared by many, including manufacturers of
switches and relays of all kinds.


==============================

Yet you still insist on using manufacturers' sales blurbs and specifications
as engineering educational standards.

Thanks for that piece of reseach Roy. My career was in the engineering
side of
Pilot devices at G.E. and thus the subject of contacts was very much
my turf.
Anybody can obtain an unused pilot device, pushbutton or what ever and
they can measure the resistance as being in the 100s of ohms area
across the N.C. contacts because of oxide build up even tho under
pressure.
If one was using one of the hand held instruments in a lot of cases it
will show as being open since the battery voltage was less than 28
volts D.C
As far as books are concerned major users such as the auto inductry
required a certain number of operations without failure where in the
past operators would just push the button again until it finally
makes.
This subject came up a few years back when computors came into the
field and the natural reaction was to use gold plated contacts but
these could not meet required criteria because gold plating is porous.
G.E were benefitted with large contracts for contact blocks e.t.c.
using reed switches and the like when the automotives decreed voltages
of less than 28 volts D.C. where other contractors failed to meet
required criteria of the customer. I could go on of course but there
really isn't any need to.
The initial statement that pressure solves things is just not true
even tho in the past when television repairmen had the opportunity of
pressing a button several times to make it operate. In todays world
buyers demand evidence of quality without the option of one or two
second tries
I am surprised that "wipe" was the most common term that you saw in
your brief search where as scrubbing action is more descriptive . Wipe
alone describes distance of button operation after the initial contact
is made which by rolling scraping action creates a side movement to
push the oxides aside. If wipe alone is required without including a
scrubbing action then wipe really only specifies available contact
wear. But on the other hand we can admit that tho English is the
common language there are differences. For your info at San Diego
there is a college for American English no less
I certainly do not advocate the use of acids to clean contacts in the
normal sense but used it as an illustration of how it could remove
oxide created by copper leaching thru the silver plating which
inevitably causes momentary failures especially with older equipment.
The same problem is avoided with reostats where they have a
sliding/scraping motion to ensure accuracy of measurement.
I have said enough since I am 'out of my turf' whereas on my own turf
the grass is growing and it needs to be cut
Regards
Art



crRoy Lewallen wrote in message ...
I just like to give the readers an option. For transmission line terms,
they can choose between HP/Agilent's usages and definitions, or yours.
For terminology regarding contacts, they have their choice between 3M's
and Richard's. And for engineering educational standards, readers can
choose among Ronold King, Terman, and Kraus, or Reg Edwards. I'm sure
each will make the choice that he/she feels most confident with.

Roy Lewallen, W7EL

Reg Edwards wrote:
It's an "abuse of language" shared by many, including manufacturers of
switches and relays of all kinds.


==============================

Yet you still insist on using manufacturers' sales blurbs and specifications
as engineering educational standards.

"Ronald Walters" wrote in message om...
I have been using a MFJ-989C tuner for about (5) years without any problems.
Just recently I have noticed that on the higher band, 24 MHz that the SWR
occasionally would jump from an adjusted 1:1 SWR to infinity. A slight
adjustment of the roller inductance appeared to solve the problem although I
haven't ruled out a balum or antenna problem. I plan on investigating that
this weekend, however, before I open the cabinet and look for problems I
would ask the group for recommendations on cleaning the roller assembly and
inductor to ensure good conductivity after I am done.

I still have some old cleaning solutions from the old TV tuner days, some
electrical cleaner (Appears heavy duty stuff) but maybe there is some other
solutions someone might recommend.

Your thoughts and recommendations are appreciated

Ron - W4LDE

Theories on wiping, etc non withstanding, the usual cause of roller
problems on that tuner, " I have one" is due to gradual weakening of
the pressure of the roller on the coil due to the weak micky mouse
design of the coil. You can tighten it up by adjustng the little
things on the end, that are locked with a hex key. But be very careful
when you are doing this. It's easy to overtighten, and then it will
bind easier. A dirty coil could be the problem, but I bet it's that
coil starting to slightly loosen up from 5 years of turning back and
forth.
It then starts to "skip" at places, due to the lack of normal pressure
against the coil. I've had to adjust mine a couple of times. If you
coil feels overly easy to turn, compared to when new, that may well be
the problem. MK

Hi,

Deoxit by Caig Labs replaces the Cramolin product.

http://www.caig.com

The D5 is a 5 % concentration and normally cleans up most dirty contacts and
surfaces.
Very little is needed.

73 luke



Richard wrote...

One contact cleaner that I used that was better than most was
Cramolin. This is a monomolecular layer solution that you would use
very sparingly. However, as your tuner did not arrive brand-new (or
brand-used) with it, your problem may be more mundane.

The simplest way to defeat corrosion is with pressure. The spring
tension of the roller may have slackened up over the years.

73's
Richard Clark, KB7QHC

On Fri, 24 Oct 2003 15:54:31 GMT, luke
wrote:

Hi,

Deoxit by Caig Labs replaces the Cramolin product.

http://www.caig.com

The D5 is a 5 % concentration and normally cleans up most dirty contacts and
surfaces.
Very little is needed.

73 luke


Hi Luke,

Thanks for your update. The suggestion of using Hydrochloric Acid for
contact cleaning is one of the most outrageous suggestions I've seen
come down the pike. I read of one poster who had obtained a gallon to
accomplish a task, who then asked "what do I do with the 99.99% left
over?"

After I had just participated in the Washington Toxic Coalition's fund
raiser the night before, the posting of indiscriminate advice that
toxic chemicals are the best choice over and beyond what is a simple
fix with Mark's allen wrench was another nail in the environmental
coffin for our children.

I fielded a contact problem for a local here and offered an even
simpler suggestion: use clean water. Complete immersion followed by
air drying at an elevated temperature works far better than a vat of
chemicals.

For those plagued with static problems, visit:
www.aclstaticide.com/
which is one of the best and safest anti-static products on the
market. You can use it as a spray or a wash, and do your floors or
carpets with it without the fear of toxicity.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
For those plagued with static problems, visit:
www.aclstaticide.com/
which is one of the best and safest anti-static products on the
market.

Is that the stuff to use on dirty pots?
--
73, Cecil, W5DXP

On Fri, 24 Oct 2003 12:56:54 -0500, Cecil Moore
wrote:

Richard Clark wrote:
For those plagued with static problems, visit:
www.aclstaticide.com/
which is one of the best and safest anti-static products on the
market.

Is that the stuff to use on dirty pots?

Hi Cecil,

No. It used to be Freon, a very heavy liquid solvent used as a wash
for dirty pots. As I offered, I use water. If the problem is not
amenable to that, replace the pot. If you gain relief from some other
product, you might be lucky that it will have solved it; or if
repetition is necessary, then you have become "hooked" on that
chemical solution (which again suggests a contact pressure problem).
One might want to investigate the logic of "wiping" in the context of
bad pots. ;-)

[hint: HCL will not work.]

73's
Richard Clark, KB7QHC

Hi,

The Caig Labs products are also very effective on switches and pots.
Deoxit D5 works great on the older radio dirty or scratchy pots, makes
them work as new.

Again, only very little of the stuff is needed to do the job.

http://www.caig.com

73 luke



Cecil wrote:

Richard Clark wrote:
For those plagued with static problems, visit:
www.aclstaticide.com/
which is one of the best and safest anti-static products on the
market.

Is that the stuff to use on dirty pots?
--
73, Cecil, W5DXP

Richard Clark wrote:

On Wed, 22 Oct 2003 12:43:20 GMT, "Ronald Walters"
wrote:

I would ask the group for recommendations on cleaning the roller assembly and
inductor to ensure good conductivity after I am done.

Hi Ron,

One contact cleaner that I used that was better than most was
Cramolin. This is a monomolecular layer solution that you would use
very sparingly. However, as your tuner did not arrive brand-new (or
brand-used) with it, your problem may be more mundane.

The simplest way to defeat corrosion is with pressure. The spring
tension of the roller may have slackened up over the years.

73's
Richard Clark, KB7QHC

How about silver polish - is that any good for this?
Someone told me it is - but I don't know.

On Mon, 27 Oct 2003 03:58:10 GMT, wrote:

How about silver polish - is that any good for this?
Someone told me it is - but I don't know.

Hi OM,

If silver polish worked, then you could as easily boil it in water in
an aluminum pan - does the same thing.

You could also use a typing eraser to clean the mating surface. This
is an old board cleaning tip that was NASA approved back when there
were typewriters to need typing erasers. These erasers had the right
amount of abrasive without having too much. The same goes for a
dollar bill having just enough abrasive (useful for cleaning fouled
relay contacts). But none of this really takes care of the problem.
It simply puts you into the lock-step of a chemical dependency.

This all returns to the same lack of need when tightening up the
contact spring would do the trick just as Mark described. The "good"
chemicals that have been suggested are not cheap, and the "bad"
chemicals (Hydrochloric Acid no less) are extremely cheap to get, but
a pain to get rid of.

73's
Richard Clark, KB7QHC