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

Richard Clark wrote in message . ..
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.

Garbage
For continued use you must have a wipe or what is termed a
scrubbing action. Period. Even with silver or gold the lack
of scrubbing action will permit intermitent contact unless
the power is high enough to blow away the oxides.
Art





The spring
tension of the roller may have slackened up over the years.

73's
Richard Clark, KB7QHC

On 22 Oct 2003 15:05:58 -0700, (Art Unwin KB9MZ)
wrote:

Richard Clark wrote in message . ..
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.

Garbage
For continued use you must have a wipe or what is termed a
scrubbing action. Period. Even with silver or gold the lack
of scrubbing action will permit intermitent contact unless
the power is high enough to blow away the oxides.
Art
The spring
tension of the roller may have slackened up over the years.

73's
Richard Clark, KB7QHC

Hi Art,

You are out of your turf. Pressure is the way all contacts work to
break the insulating barrier formed by oxides. Your typical abuse of
language here with "wipe" is another example that demonstrates
pressure. The indiscriminate use of chemicals to treat a mechanical
problem is one that I have demonstrated as being wholly unnecessary:
none of your new gear, nor any old gear just acquired that works fine
came with this chemical bath treatment.

Long before anyone here was born, precision contacts were tapered
plugs that fit into tapered sockets. The sockets were bifurcated
(split in two halves) such that the plug created the closure between
them with a simple insert and twist to break the layer of oxide.
Note, there is no "wipe" as the twist translates the torque into
pressure (wiping has nowhere to deposit what is "wiped" away in the
tapered socket). No one needed sandpaper or a bottle of acid to erode
the surface and corrode other parts through the solvent's vapor (a
very insidious imposition). There is a very good reason why
electronics manufacturers avoid acid core solder (unless they use a
water wash down following board construction and faithfully use rosin
core solder for touch up work - with extreme care not to mix the two
solders).

For contacts that have little pressure, the voltage presented across
them can penetrate the barrier; however, there are applications where
those voltages are not sufficient, and when the contact pressure is
not enough either, you get into these problems. Mechanical TV tuners
back in the early days suffered this problem and a special grease
surfactant was used to insulate the contact face from corrosion while
the pressure was sufficient to displace it for electrical contact.

73's
Richard Clark, KB7QHC

It's an "abuse of language" shared by many, including manufacturers of
switches and relays of all kinds. A google search on "contact 'wiping
action'" brought around 3000 hits. The few I glanced at dealt with just
that topic, using those words.

The only contact-related document I have readily at hand is a 3M catalog
of "Electronic Interconnection Systems". Just about every connector has
a specification for "wipe area" or "wiping area".

Roy Lewallen, W7EL

Richard Clark wrote:

Hi Art,

You are out of your turf. Pressure is the way all contacts work to
break the insulating barrier formed by oxides. Your typical abuse of
language here with "wipe" is another example that demonstrates
pressure. The indiscriminate use of chemicals to treat a mechanical
problem is one that I have demonstrated as being wholly unnecessary:
none of your new gear, nor any old gear just acquired that works fine
came with this chemical bath treatment.

Long before anyone here was born, precision contacts were tapered
plugs that fit into tapered sockets. The sockets were bifurcated
(split in two halves) such that the plug created the closure between
them with a simple insert and twist to break the layer of oxide.
Note, there is no "wipe" as the twist translates the torque into
pressure (wiping has nowhere to deposit what is "wiped" away in the
tapered socket). No one needed sandpaper or a bottle of acid to erode
the surface and corrode other parts through the solvent's vapor (a
very insidious imposition). There is a very good reason why
electronics manufacturers avoid acid core solder (unless they use a
water wash down following board construction and faithfully use rosin
core solder for touch up work - with extreme care not to mix the two
solders).

For contacts that have little pressure, the voltage presented across
them can penetrate the barrier; however, there are applications where
those voltages are not sufficient, and when the contact pressure is
not enough either, you get into these problems. Mechanical TV tuners
back in the early days suffered this problem and a special grease
surfactant was used to insulate the contact face from corrosion while
the pressure was sufficient to displace it for electrical contact.

73's
Richard Clark, KB7QHC

On Thu, 23 Oct 2003 10:40:36 -0700, Roy Lewallen
wrote:

It's an "abuse of language" shared by many, including manufacturers of
switches and relays of all kinds. A google search on "contact 'wiping
action'" brought around 3000 hits. The few I glanced at dealt with just
that topic, using those words.

The only contact-related document I have readily at hand is a 3M catalog
of "Electronic Interconnection Systems". Just about every connector has
a specification for "wipe area" or "wiping area".

Roy Lewallen, W7EL


Hi Roy,

And does that render the issue of pressure as "garbage" or negate any
comment offered by myself? Does it elevate the injudicious
application of chemicals? Does it replace common sense? Many of the
mythical lurkers might be lead down the primrose path of dunking their
'tronics into a vat of Coca Cola simply because of its Phosphoric Acid
content.

Is a google search the barometer of accuracy for
rec.radio.amateur.chemistry when supported by 3000 hits? If so,
"tits" would eclipse the charts. ;-)

73's
Richard Clark, KB7QHC

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.

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.

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