And you had to
re-solder some inter-board connecting wires on the core
 memory modules.  IIRC these wires were little strips of springy stuff. 
 I'm not sure I count faults that _I've_ caused. The core memory soldering
 failed when I dismanted a core module to show some people how it worked.
 Had I left it assembled it would probably have carried on working. 
 
Perhaps it would.  But that doesn't mean you caused the fault.  A dry joint
is still a fault; even if you are the one who makes it lose contact, it
wasn't you who made the joint dry...
Philip.