Blocks Lost/Position Lost Error on Backup Operation

This Field Change Order (FCO TA81-I001) provides instructions for reworking TA81 Tape Transports equipped with STI Controller Modules (P/N 77042145 and below). The rework is intended to fix errors labeled "Blocks Lost" or "Position Lost" that occur during VMS Backup operations due to an incorrect acknowledge setting at the start of a transfer. The procedure involves removing the STI Interface module, replacing specific ROMs (G2, G4, and G6), and performing necessary dip switch adjustments and system verification tests. The document includes a note for US-based technicians to return the replaced old ROMs to Digital Equipment Corporation in Shrewsbury, MA, due to component shortages.