Defective IBM core memory UPDATE.

From: Henk Stegeman <>
Date: Sat Jan 1 03:34:22 2005


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

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.

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.

Received on Sat Jan 01 2005 - 03:34:22 GMT

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