In reply to:

the usual form of fixing them used by the technicians involved picking it up about a foot and dropping it back to the table.



You sure that wasn't an Apple III? Quote from http://fp3.antelecom.net/gcifu/applemuseum/3.html

From what I have read, the original Apple III (or Apple /// as it was written) ran so hot that it's board would expand and unseat the chips from their sockets. At one time the recommended fix for an Apple III that was acting up was to drop it about 2 inches onto a hard surface to reseat the chips!
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