VAX memory controller bug

[mhtsa!allegra!psuvax!red]

Our VAX 11/780 with 1.5Mb of memory  was  recently  diagnosed  as
having  memory  controller  problems due to 74S373 ICs which were
unable to drive a high capacitance load.  This problem apparently
manifests  itself  only  in systems with more than 1Mb of memory,
and may be either cause intermittent or consistent failures.   On
our  particular  system  the symptoms were initially intermittent
and gradually became more serious.  Two VAXen delivered within  a
week of each other (6/80) to the CmpSc and EE departments here at
Penn State were both found to have "possibly" faulty chips (Texas
Instrument  74S373 with a date code of 7840A or later).  Replace-
ment of the controller board has apparently solved our problem.

        - Ralph Droms (psuvax!red)