If my CDC 160-A memory goes, there's no more
core memories.
Core memory can be repaired, but it isn't fun.
So far, thankfully, all my core memeory system failures have been in the
driver electronics, not the core planes. Yes, there are some critical
timing and current adjustments in the drivers, but the problems I've had
have been discrete transistors that have gone open-circuit and I've
managed to find suitable replacements (sometimeswith a bit of 'select on
test'ing.
-tony