[Milsurplus] DIFAR

[CL in NC]

My first association with DIFAR was in 1971.  I remember it had a 1MB magnetic core memory that supposedly cost 1 million bucks back then.  It had multilayer boards, each board stacked one on top of the other, their surface covered with small ferrites that were magnetized one way for a one, the other for a zero.  Those things were actually repaired, by locating the bad trace, and running #40 enameled wire to complete the connection from one point to the other, bypassing the bad trace.  When I say 'locate', it was not a computer running diagnostics, it was a fellow with a Simpson 260 and knowledge of how it worked to figure out what invisible bit of copper was broken.  It was classified a 'Confidential' item back then, that means it was a secret item before that, and wonder just when it was first put in service.  Remember when the SR71 was made public, and it had been unknown for many years before that?

Charlie, W4MEC in NC