FCO 85XBA-1009, Overvoltage fault in the H7187 reg

This Field Change Order (FCO 85XBA-1009) addresses an overvoltage fault in the H7187 regulator of VAX 8530/8550 systems, triggered by power interruptions under five seconds. The issue affects 2,551 systems shipped between January and July 1988 with BBU compliant MPS backplane Rev. D.

The solution involves replacing the H7060-A power supply regulator if its revision is below "B6" with a new "B6" or "B7" revision part (EQ-01535-01). The installation procedure includes shutting down the system, de-energizing it, implementing ESD precautions using a Velostat kit, locating and replacing the regulator, and finally powering up the system and updating records. The estimated installation time is 1 hour, with parts available from February 1989.