John Letsinger asked:

>We are looking at a unnamed manufacturers board that has several connectors
>mounted on a board.  The connectors are soldered on one side of the board.
> The connector pins are gold plated, and appear to have a silicon type
>lubricant on them.  Can connectors be purchased with a lubricant on them, or
>is it put on by the assembler, or should there even be a lubricant on the
>pins?

Yes, yes, and yes (Bellcore requires this).

>Could it be something else besides a lubricant?  I recall in the past
>that we put Dow Corning DC-4 on some rf connectors to prevent oxidation and
>water intrusion.  Appreciate any comments.

Well it _might_ be anything, unspeakable crud, old mayonnaise... ;-)

It is likely not a silicone. I do not believe silicones are good for this
purpose. Paraffin wax is sometimes used, but the best lubricant is Monsanto
OS-138 or OS-124 which is a 6/5 ring polyphenyl ether. It is clear, inert,
and very viscous at normal temperatures. It must be thinned (2% v/v) with
solvent to apply by dipping, spraying, or brushing on the contact surfaces.

It seals the fissures in the plating to protect the base metal from
oxidation, and as a physical lubricant to reduce wear of the gold during
mating and unmating cycles.

If you want to buy some, I recommend:

Nye Synthetic Lubricants
12 Howland Rd
Fairhaven, MA 02719
508-996-6721

They offer these prepared with appropriate solvent. A very nice old Yankee
company, dating back to the sperm whale oil business. They are experts in
specialty lubricants and quite friendly (for New Englanders).

Connector manufacturers do offer pre-lubricated connectors in some cases,
in other cases they will play dumb or say it must be done by the assembler.


regards,

Jerry Cupples
Interphase Corporation
Dallas, TX USA
http://www.iphase.com