Write Back Cache Batteries

This Field Change Order (FCO HSWBC-0001) addresses a potential reliability issue with batteries installed on specific Write Back Cache modules between April 1 and July 15, 1995. These batteries may fail to maintain a reliable connection, leading to possible data loss if the controller loses power. The document provides instructions for:

• Identification: A physical inspection process to determine if a battery is suspect based on label markings.
• Solution: Disabling Write Back Cache functionality on affected controllers until batteries are replaced.
• Replacement Procedures: Step-by-step guidance for replacing batteries, tailored for different controller configurations (non-redundant vs. redundant systems).
• Safety: Necessary Electrostatic Discharge (ESD) precautions to be observed during module handling.

Technicians are instructed to return suspect batteries to Digital Equipment Corporation for disposal or rework.