28 Aug
2015
28 Aug
'15
6:31 p.m.
On Fri, 28 Aug 2015, Chuck Guzis wrote:
On 08/28/2015 07:42 AM, Tothwolf wrote:
I think I've answered my own question today while looking at a datasheet
for another type of solder. My guess is that the solder they used did not
contain any copper, and the tin in the solder IBM used dissolved small
amounts of the already very tiny copper wires, creating a weak point where
the wires were soldered to the terminals.
Lyle, was there any discussion of possibly laser welding replacement stubs
of wire before the breaks that could then be re-soldered to the terminals?
That would seem to be a viable repair option, although it would require
special equipment.
With all the different solder alloys I work with
regularly, I have to
ask...what type of solder caused that sort of damage? Was it the alloy
itself, or did IBM use a flux which was too active and then failed to
clean away all the residue? If they used a rosin-based flux, was it due
to the specific activator used in the flux?
That's actually a little puzzling. 1401 core frames have survived well
(got one in my desk drawer). You'd expect that the same process would
be used for equipment that's pretty close to contemporary.