TUK50 UNIBUS Controller Module Maintenance

This document outlines the Field Change Order (FCO) TUK50-I001, which describes the procedure for upgrading TUK50 UNIBUS controller modules (M7547) below revision C2. The upgrade resolves issues such as 'Not software enabled' system hangs, phantom device address messages, and excessive soft errors during backups. The procedure involves replacing two ROM chips (positions E48 and E49) with updated components, setting a switch for hardware revision 3, and marking the module handle as Rev C2.