Defective IBM core memory UPDATE.

Hi, UPDATE: I decided to open the core stack of my spare storage module to check if the open X wires where repairable. After opening the stack carefully at a plane with two open X wires I found out that the open spot in the X wires where located at the black 'foam' which IBM had put in between planes for airflow reasons. See white arrows in http://home.hccnet.nl/h.j.stegeman/CoreProb3.JPG The X wires where broken by a chemical reaction between the copper wires and the black 'foam'. This 'foam' becomes over the years very sticky black tar. I now also understand why only X wires where open and none of the Y wires. I also checked the tension/slack in the X/Y wires to see if shrinking (by frost) could break them. This is not the case. Conclusion: It was not the unheated storage of the system (my resposibility) but the chemical timebomb between the aging 'foam' and the X wires that caused the defect in all my core modules. I am now planning for a chip replacement of these core modules. Henk