IBM PS/2 8580 Power Supplies

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 non-IBM 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 16-bit adapters will probably require 7 to 10 watts each and IBM 32-bit adapters will probably require 7 to 13 watts each. The information available on original fixed disks is dated, but suggests:

Fixed Disk
Physical size Power in Watts
44 MB ST-506 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.:

8580 Power Connector

-Lead Pin
+Lead Pin
V dc Minimum
V dc Maximum
+ 6.2
+ 6.2

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 .