Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember tony sayer
saying something like:

The Japanese were the first to introduce re-cycled copper in their
mass-market looms, which led to all sorts of mysterious faults in the
wiring in later years.
Grimly .. how did that manifest itself, and what was "wrong" with the re
cycled copper?...

Mostly corroded connections to crimps and sometimes wire breaks where
the insulation had allowed moisture to permeate through. A bit late for
it now, but if you had a look on many Japanese wiring looms of the 60s
and 70s, you'd find the copper had corroded not just at the ends, as
expected, but all the way through the length of the wire. I put this
down to the re-cycling of scrap copper, with impurities above the level
that would have been acceptable in Europe.


NO.

I suspect its a subspecies of this:

http://www.barbadosrc.org/misc/blackwire.php

which is well known, if not so well understood.

I suspect myself its electrochemical attack of copper due to three
things: damp, a salt, and a voltage.



//snip

What the Japanese seemed to do was improve the protection, rather than
improve the quality and cost of the metals. They concentrated on better
insulation and shrouding, with much more attention paid to securing the
loom, and with alloy castings they depended on laquer coatings. This has
been going on for decades now.

precisely. There was nothing wrong with the copper, but they needed to
keep the damp and the salts out better, that's all.