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Re: gEDA-user: Contact reliability

Karel Kulhavy wrote:

How would the human check? Sometimes when thermal creep moves oxidized and
nonoxidized areas around, the impaired device start and stops working randomly.

Is there some bad-contact-o-meter where you stick probes into the circuit and
the display will read
"On February 14 2007, 16:07:15 UTC, this contact will temporarily fail, the
packetloss pattern will be:
!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!.!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!1..!!!!!!!!!!!!!!!!!!.................!!!!!!!!!!!!!..!!!.!!.!!!
!.!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1...!!!!!!!!!!!!!!!!!!!!!!...!!!!
"?

Well, in that case I don't know. Guess I didn't read your first email carefully enough.

Ok.  Here is my practical recommendation.  All low tech, readily available.

Attach crimp-on ring terminals to the ends of the wires.
Solder the ring terminals (after crimping) by dipping in pot of melted solder.
Use lots of old fashioned hard to clean solder flux dissolved in high volatile solvent. Dip wire in flux before crimping. Dip whole ring-terminal after crimping.
Select ring terminals with long barrels (the cylindrical part) and brazed seams and no insulation sleeve, like the ones from 3M.
Obtain a professional grade ratchet crimper, that puts a dimple in the barrel, rather than just sequeezing it. Use the exact right size die in the crimper.
Scrape off any excess solder bumps on the ring (screw clamping region) with a knife.

Use ordinary off-the-shelf screw terminal blocks, with nickel plated parts.

Spray assembly with sticky grease.

I think this will last longer than you will.

All that is needed for field maintenance is a screw driver, some spray solvent to wash the dirt off the terminals, perhaps a knife to scrape off some corrosion, and spray grease to cover it back up again.