As Karl noted previously, the Right Septum power supply had been set to 4800 amps. This drove the supply to either all it could put out or 1050 amps, whichever is the lower amount of current. The software limit is 1050 amps. The comm error usually is only present when the AC power is off. When we got in the hall the 480VAC was not there, the breaker on the wall panel had tripped. I reset the breaker and the supply came back up, apparently ok. I set both septum power supplies to 50A and then to 480 amps. I also inadvertently typed 4800 for the Right Septum, but corrected it before anything got into trouble. We left both of the Septa at 480 amps. It also looked like the network switch in the Left Shield House, under the Boxbeam, was down. When I got under there I found one of the AC power switches had all of its outputs turned off. This meant iocha14, iocha18, one of the HP3458s for current readback of the dipole, nbha0, nbha3, and the Q2/Q3 DACs were all off. I cycled power on both of the AC power switches and everything came back up. On the Fortress UPS these are plugged into, nothing happened when I pressed the Test button. I'm not sure I was doing it correctly. I could see the voltages looked ok and the load was 45% with 8 minutes of run time capability. It seems the softIOCs for the curent readbacks got hung-up. There was no readback of the current for the Q2/D1/Q3, so I turned the power supplies off on the Left Arm. It looks like the Septum supply problem and the Left Arm problem are not directly related. The time between the problems is sizable. The Left Arm problem is reminiscent of PREX running conditions, I suspect a high background in the hall. The top VDC chamber on the Left Arm tripped off at some point. All this will be looked at in more detail tomorrow, well..., later today.