The power supplies have the same size and shape for all models of the 8580 as well as the 8560. However, there is some variation in their power capacities. Earlier models of the 8580 are rated at 225 watts, and later models were 242 watts. The 8560 models are either 207 watts or 225 watts.
When using the smaller wattage power supplies, it is advisable to use caution when the number of drives and adapters approaches the maximum. I understand that tables were available which allowed calculation of the total actual power requirement. If someone can locate this information on the web, I will provide a pointer here. Otherwise, the information is sometimes available within the IBM announcement letter, sometimes within the appropriate IBM Technical Reference document, and various OEM sources for nonIBM parts. I expect that any problems will probably result with the use of "older" adapters and full height disk drives. For example, the maximum power requirements for the 8514/A Display Adapter are 16 watts on the +5 volt supply and 0.22 watts on the 12 volt supply!
In order to assist with power calculations, you will find some valuable
information at this IBM
Support Site..
Information available in the IBM
Personal System/2 Reference Guide suggests that IBM 16bit adapters
will probably require 7 to 10 watts each and IBM 32bit adapters will probably
require 7 to 13 watts each. The information available on original fixed
disks is dated, but suggests:


Physical size  Power in Watts 
44 MB  ST506  5.25 in.  31  39 
70 MB  ESDI  5.25 in.  31  39 
115MB  ESDI  5.25 in.  31  39 
314 MB  ESDI  5.25 in.  35  42 
60 MB  SCSI  3.5 in.  13  19 
120 MB  SCSI  3.5 in.  13  19 
For the really serious technical types, Louis Ohland has provided the
following diagram of the minimum and maximum voltages available from the
connectors of these power supplies. The nominal values are either 5V and
12V, of course.:

Al Savage has recently posted a repair that he has made to one of his
8580 power supplies. There is considerable risk in attempting to repair
any power supply if you are not familiar with with them, and no schematics
have been released to the public in order to deter such repairs. However,
if you are willing to assume the inherent risks, the details are available
here .