and if you had one bit bad...
...you had a whole page bad.
I was working on some circa 1950s gear and we had a unit go bad, the block used to "seal off" the ferrite core array from the environment degraded and cracked (it was bakelite), thus causing one of the sense wires to corrode and separate, rendering the whole unit inoperative. I was sent to the US Air Force Institute of Technology, given training in micro-percision soldering and using thier speciallized equipment, to include a motion reduction rig (kind of like a manual robot rig that reduced your motion by a factor of ten or more)and a biocular microscope, was able to effect a repair.
The issue was not with cost of replacement, but the fact that no replacements were avialable anywhere, and that the original vendor no longer had anyone with the talent to make new ones (Japanese garment workers if I recall properly).
