On Sun, 30 Aug 2015, Dave G4UGM wrote:
On Sat, 29 Aug 2015, Tothwolf wrote:
IBM had special machines to position and thread them.
http://ibm-1401.info/IBMCoreArraysIEEEMagnetics1969.pdf
Thanks for posting that. Very interesting. Looking at it, the machines are
extremely complex, but I am sure they could be reproduced, albeit at a
probably prohibitive cost...
.. I have marked for later reading...
Something else I forgot to mention, is that on page 8 in that pdf file,
they mention initially using 60/40 tin-lead alloy solder for the enamel
wire to the core plane terminals. On page 9, they describe switching to
20/80 tin-lead so the solder would dissolve less copper from the enamel
wire.
If repair of the core memory in CHM's IBM 1620 is ever attempted, I think
either low-tin solder alloy with 1-2% added copper or possibly a more
modern indium-lead solder alloy would probably be the best choice for the
enamel wire to terminal connections since that would greatly reduce the
likelihood of any future wire breakage.
