FCO 9XXX-0009, Airflow/temp sensors register false trips

This document is a Field Change Order (FCO 9XXX-0009) addressing false trips registered by airflow and temperature sensors when the VBox option is installed on VAX 9000-2XX and VAX 9000-4XX systems. The solution involves replacing specific airflow and motor speed control sensors with updated versions.

For VAX 9000-2XX systems, part 12-28780-05 is replaced with 12-28780-06, and 12-28779-05 with 12-28779-02. For VAX 9000-4XX systems, 12-28780-09 is replaced with 12-28780-11. The FCO requires 1.5 hours and a Field Service Maintenance Kit.

The document provides detailed step-by-step removal and installation procedures, first for 9000-210 systems (a variant of 9000-2XX) and then for 9000-4XX systems, covering tasks like system shutdown, plenum removal, sensor replacement, and reassembly. It also specifies reporting the activity on a LARS form. Necessary parts are listed, including EQ-01635-01 (12-28780-06 and 12-28779-02) and EQ-01635-02 (12-28780-11).