FCO 9XXX-0008, ALPHA particle effects causing intermittent errors

This Field Change Order (FCO 9XXX-0008) addresses a problem of intermittent errors in VAX 9XXX systems and field spares, caused by ALPHA particle effects. These anomalies can manifest as undetected incorrect results or non-recoverable data parity errors.

The FCO mandates a retrofit solution that involves upgrading the P1003-AA MUL Multi Chip Unit (MCU) and the P1004-AA FAD MCU to revision H02. While P1003-AA MCUs at revisions "E" and "F" are deemed acceptable in currently installed systems due to new encapsulant, all associated spares for the P1003-AA MUL MCU (including revisions "E" and "F") must be updated to revision "H" to ensure they are screen-tested. The upgrade aims to simulate the exposure to ALPHA particles and enhance circuit stability through a dual feedback latch.

Installation of this FCO is estimated to take 4.0 hours for a UNI CPU configuration, including shutdown, component removal, installation, and testing. It requires console software at BL14.2 minimum and references the VAX9000 Maintenance Guide. The FCO includes detailed steps for identifying affected MCUs (P1003-AA at or below revision "D", P1004-AA at or below revision "F"), replacing them with the revision "H" parts from the provided kits (EQ-01623-01 and EQ-01623-02), and performing extensive diagnostic tests to verify the fix.