[time-nuts] DC distribution

[jimlux]

On 10/4/19 1:41 PM, Poul-Henning Kamp wrote:
> --------
> In message <5D979AC0.80304 at rogers.com>, MLewis writes:
> 
>> With audio signals, a soldered crimp is one of the worst possible
>> connections.
> 
> Dabbling in audio-homoepathy are we ?
> 
> No, don't bother responding unless you have a reference to peer-reviewed
> scientific documentation for you claim.
> 


well..
https://nepp.nasa.gov/files/27631/NSTD87394A.pdf

doesn't give why, and doesn't explicitly say "don't crimp and solder" 
but does basically say "crimp crimp connectors and solder solder connectors"

TE "Crimp Theory Fundamentals; Advanced" - explanation of what makes a 
good crimp, doesn't discuss solder
https://www.youtube.com/watch?v=bAO9eCS65jw

There are actually splices designed to be crimped and soldered - but I 
suspect their applicability is for specific applications.


On Monday, I will try to find one of the connector reliability people 
for some references.  One challenge is that these practices ("don't 
solder crimped connectors") have been around for a long time (at least 
70 years), so there may not be recent published information on it. 
(recent papers I found on solder joint reliability are all about PWB 
connections - esp BGA, CGA, etc.)

And, to be honest, materials have changed.

There is *great* resistance to changing any assembly and workmanship 
standard - nobody wants to be the person who says "we don't need to do 
*that* anymore" and then a disaster happens, and one of the potential 
causes is "you didn't do *that*"

It is entirely possible that the original rationale and explanation is 
no longer valid.

There is no question that in a vibration environment, solder is 
deprecated (it's hard, brittle, work hardens, etc), not to mention all 
the issues with RoHS.  That said they do use solder joints in high 
reliability systems - just with attention to the support of the wire.

https://www.tandfonline.com/doi/full/10.1080/14686996.2019.1640072
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100029736.pdf