FCO 885BA-0001, μVAX Console fails to load μCode/diag into CPU

This Field Change Order (FCO 885BA-0001) addresses a critical issue where the Microvax Console Subsystem on VAX 8820/8830/8840s fails to load microcode or diagnostics into the CPU. The root cause is identified as the M7553 QC module propagating noise on the CC reply line, leading to improper data strobing.

The FCO mandates replacing the existing M7553 QC module with a C3 revision (part EQ-01481-01), which updates the 630PS Console to revision "C3" and the 885BA CPU System Kernel to "C1". The installation process, estimated to take 0.5 hours, involves powering down the uVAX, disassembling parts to access the module, implementing strict ESD safety precautions using a VELOSTAT kit, and replacing the M7553 module. After installation, specific console commands (Resync, Show Status, Show Power, Set Terminal Program) are required to verify proper functionality. The document also specifies reporting this activity on the LARS form. This FCO applies to all affected Microvax 630PS Console Subsystems, including field service spares and self-maintenance customer orders.