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legg legg is offline
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Default Flakey Molex(?) connectors

On Tue, 18 Jun 2019 08:38:13 -0700, John Robertson
wrote:

On 2019/06/18 8:04 a.m., legg wrote:
On Tue, 18 Jun 2019 07:51:07 -0700, John Robertson
wrote:

On 2019/06/18 7:34 a.m., wrote:


If they're tin plated, they are not good for small signals. The
contact surfaces can usually be restored by simply pulling and
reinserting the connector a few times. Square pins can be brushed
clean. The problem will reoccur. It can be agravated by mixing tin
with gold flash (pins vs receptacles. Sometimes the gold flash in the
receplacles is local and hard to identify.

Depending on humidity and temperature levels, the tin/tin contacts are
good for between 6 and 10 years, between cleanings.

RL

google "fretting" corrosion.

can be insidious to troubleshoot

mark


Thanks for that info - I went to one link:

https://www.windpowerengineering.com...o-do-about-it/

where they talk about fretting corrosion in wind turbines. Even when
there is lubrication fretting corrosion occurs, but it is more benign
with lubrication as opposed to no lubrication.

So I suggest folks look at something like Dow Corning #4 dielectric
grease for connectors that experience any vibration to increase the MTBF
of the connection(s). I know DC#4 helps my games run longer between
service.

Others swear by De-Oxit, but the resulting contact protection is
probably similar.

John :-#)#


That's a mechanical failure in iron-bearing materials.

The small signal electrical contact failure is straight oxidation of
tin.

RL


I dunno, I've seen a lot of contact failure over the years and fretting
would explain some of what I am seeing. And a product like DC#4 (now
called Molykote) helps prevent failure by providing both mechanical
(friction reduction) and electrical protection:

https://www.dupont.com/content/dam/D...10-1187-01.pdf

John :-#)#


Contact coatings are useful when non-optimal materials benefit from
protection from oxygen, but small signal connections are best achieved
just using the right materials. Tin isn't the right material.

RL