The Peripheral Bay Backplane voltages problem was resolved by replacing the 2-bay SCSI cage assembly (328WD Rev A00 backplane) with a cage assembly (4575D Rev A00 backplane) from another PE4400. I'm guessing that the part number difference on the backplane was not a factor, but I have no real way of knowing that without getting another 328WD backplane, and I don't see a point in doing that.
I have recently installed OMSA 4.5 on a Linux system to try to identify why the front panel error lights are blinking.  The summary report is: $ omreport chassis Health Main System Chassis SEVERITY : COMPONENT ... Non-Critical : Fans ... Critical : Voltages ...  I figured out how to correct the fans issue, but it is not so clear how to approach handling the Voltages issue on such and old platform. $ omreport chassis volts Health : Critical  ...  Index : 21  Status : Critical  Probe Name : Peripheral Bay Backplane +5V  Reading : 6.630 V  Minimum Warning Threshold : 4.750 V  Maximum Warning Threshold : 5.250 V  Minimum Failure Threshold : 4.500 V  Maximum Failure Threshold : 5.500 V  Index : 22  Status : Critical  Probe Name : Peripheral Bay Backplane +12V  Reading : 10.550 V  Minimum Warning Threshold : 11.520 V  Maximum Warning Threshold : 12.480 V  Minimum Failure Threshold : 11.400 V  Maximum Failure Threshold : 12.600 V    Any ideas?  Is it more practical to move the system to different hardware than to attempt resolution of these issues?  Also, what is the Peripheral Bay Backplane, is it field replaceable, and does it have a part number usefule for locating a replacement?  I have another 4400 that is in an unknown state (no OS, etc.), so conceptually I might be able to rob parts off of it, or transfer the RAID containers to it.
PowerEdge 4400 Critical fault Peripheral Bay Backplane +5V/+12V