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Subject:
From:
Karen Tellefsen <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Karen Tellefsen <[log in to unmask]>
Date:
Fri, 10 Sep 2010 15:15:36 -0400
Content-Type:
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Parts/Attachments:
text/plain (406 lines)
Of course the gold plating on Gameboy plug-ins is shoddy and porous and 
the green is copper corrosion products. Sulfates would certainly be 
present if air pollution were the major reason for the corrosion, however 
in the case I described, the major reason for the corrosion was saliva. 
Certainly chloride is present in saliva, but not a lot of sulfate.  A 
boy's mouth is a very humid environment.

Tin contact are necessary for fretting, mating tin to gold exacerbates 
fretting a lot.  I would suspect the the mating connector on the Gameboy 
also has a crummy gold flash, so fretting is unlikely an issue.

Hopefully Gameboys are assembled with lead-free solder.

.

Karen Tellefsen - Electrical Testing
[log in to unmask]
908-791-3069




From:   Bob Landman <[log in to unmask]>
To:     TechNet E-Mail Forum <[log in to unmask]>, Karen Tellefsen 
<[log in to unmask]>
Date:   09/10/2010 02:51 PM
Subject:        Re: [TN] humid environments and long term reliability



Dear Karen,

According to Dr. Henning Leidecker at NASA Goddard SFC and Dr. Craig 
Hillman at DfR, the green is corrosion in the pits in the cheap thin gold 
flashing.  Unless the gold plating is very thick, it will have many pores 
exposing the base metal to the atmosphere.  Gold, of course, does not 
tarnish so the green stuff has to be chlorides or sulfates of the base 
metal.

see http://www.dfrsolutions.com/uploads/white-papers/Gold_Flash.pdf

As for "dielectric grease" - the contact pressure forces an intimate metal 
to metal connection; the lubricant does not insulate the contacts.

Yes, I used q-tips for all the applications.  A tiny bit of the lubricant 
is all that's needed.  More is not better.

Don't believe the USAF or NASA or DELPHI?

http://connectors.delphi.com/dcsgdmcs/Del/attachments/Promotions/fretting.pdf


Then you will have to live with corrosion because the atmosphere will 
cause fretting corrosion on all connector contacts eventually as the 
smallest vibration will move the contacts just enough to cause the 
problem.

In a vacuum, there is no oxygen or other gases so there is need for the 
lubricant.

Bob Landman
H&L Instruments, LLC
LDF Coatings, LLC


On Sep 10, 2010, at 7:22 AM, Karen Tellefsen wrote:

> I noticed a rather  unusual corrosion-related electronics failure on 
> Monday evening.  My husband and I were having dinner at a local 
> restaurant, and the man sitting next to us was cleaning corrosion off a 
> game plug-in from his 7 year old son's Gameboy, so I asked if I could 
look 
> at it.  Gold contacts with green corrosion products, little plastic 
ridges 
> between the contacts.  The boy would put the plug-ins in his mouth, then 

> put the plug-in in the device, and this would result in galvanic and 
> electrolytic corrosion. 
> 
> I told the boy not to put his games in his mouth because it spoiled 
them, 
> and told his father to try a soft paint brush and rubbing alcohol at 
home.
> 
> I think this one is stranger than Bev's  Blackberry failures,
> 
> Karen Tellefsen - Electrical Testing
> [log in to unmask]
> 908-791-3069
> 
> 
> 
> 
> From:   Victor Hernandez <[log in to unmask]>
> To:     [log in to unmask]
> Date:   09/10/2010 08:52 AM
> Subject:        Re: [TN] humid environments and long term reliability
> Sent by:        TechNet <[log in to unmask]>
> 
> 
> 
> Chris,
> 
> What is the 760G product?   Dielectric grease!
> 
> Victor,
> 
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Chris BALL
> Sent: Friday, September 10, 2010 7:48 AM
> To: [log in to unmask]
> Subject: Re: [TN] humid environments and long term reliability
> 
> " I have several HP calculators that used to be intermittant (battery
> contacts) until I took a q-tip and applied 760G on them.  Also several
> flashlights and the trailer hitch on my Volvo wagon."
> 
> ...must be one hell of a q-tip....
> 
> :-)
> Chris
> 
> 
> 
> On Sat, Aug 28, 2010 at 1:31 PM, Bob Landman 
> <[log in to unmask]>wrote:
> 
>> Carl,
>> 
>> We had a problem years ago with Molex/Amp tin-plated power connectors
>> (0.156" spacing).  We traced the problem to corrosion (we could see the
>> discoloration on the pins caused by the humid enviroment + airborne
>> contaminants).  We contacted Molex who recommended Nye Lubricants 
Nyogel
>> 760G connector lubricant.
>> 
>> At the time I happened to be visiting Henning Leidecker and Jay Brusse 
> at
>> NASA Goddard Space Flight Center so asked them for advice. I  was 
> advised to
>> read the following paper.
>> 
>> http://www.agingaircraftconference.org/all_files/20/20c/123_doc.pdf
>> 
>> That convinced us we were on the right track (we had been concerned it 
> was
>> a circuit design or component problem as the falures were random).
>> 
>> We sent the client a tube of 760G which he applied to over 200 of our 
> units
>> in 2007.  The problem (intermittant power failure) vanished.
>> www.nyelubricants.com   We now apply 760G to all our tin-plated
>> connectors.  Also some gold plated connectors (RJ-45 type) as we found 
> in
>> some environments (like sewage treatment plants) the atmosphere quickly
>> finds and corrodes the tiny pinholes in the gold flash coating.  Unless 

> the
>> mfg plates a very thick gold coating, you can expect such imperfections 

> to
>> corrode.  The result is a greenish tarnish which is an insulator.  I 
> have
>> several HP calculators that used to be intermittant (battery contacts) 
> until
>> I took a q-tip and applied 760G on them.  Also several flashlights and 
> the
>> trailer hitch on my Volvo wagon.
>> 
>> Regards,
>> 
>> Bob Landman
>> H&L Instruments, LLC
>> 
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Carl VanWormer
>> Sent: Monday, August 23, 2010 1:53 PM
>> To: [log in to unmask]
>> Subject: [TN] humid environments and long term reliability
>> 
>> We are considering conformal coating our boards that will go into a 
> chassis
>> that may be an occasional high humidity environment.  I have been told 
> that
>> the humidity (and water) is "slowed down" by the conformal coating, and 

> that
>> good cleaning before the conformal coating is essential for 
reliability.
>> Assuming we have done all we can do for the PC board assembly, my worry
>> goes to the next level; the cables that connect between boards and also 

> to
>> the valves, relays, and sensors.  Is it worth considering messing up 
the
>> system with silicone grease smeared on all of the 2-pin, 5-pin, and 50 
> pin
>> (IDC) plugs and sockets?  I know some of the cute little phone-wire 
> crimp-on
>> IDC button connectors are filled with a dielectric grease, so it must 
> have
>> some value.  And what about the IDC connector, with its pins just 
> piercing
>> the ribbon cable .
>> . .  Is there a long term reliability problem there, too?
>> 
>> 
>> 
>> I'm looking for "fatherly guidance" on making a system that won't ever 
> need
>> a field service call.
>> 
>> 
>> 
>> Thanks for tolerating my paranoia,
>> 
>> Carl
>> 
>> 
>> 
>> 
>> 
>> 
>> 
>> Carl Van Wormer, P.E., AE7GD
>> 
>> Senior Hardware Engineer
>> 
>> Cipher Systems
>> 
>> 1800 NW 169th Place, Suite B-100
>> 
>> Beaverton, OR  97006
>> 
>> Cipher Systems (503) 617-7447 x 5163
>> 
>> Direct Line (503) 425-5163
>> 
>> [log in to unmask]
>> 
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