First of all, you need to find which module is causing the fault. Do you have some sort of basic card, serial module or other specialized module in the rack? If I remember correctly, the last time I saw this, the maintenance techs replaced a specialized module without regard to dip switch settings. Another time, the slot number the fault number associated with was one more than the actual module that was bad. That took some time to figure out, and AB's tech support was useless.David