I have been through a few thousand S+ machines but have yet to come across my first bad power supply (just one of the things I love about the S+). The supplies are over-designed so reliability is extremely good. I do however see people replace the power supply while troubleshooting a problem that is ultimately caused by the power supply harness. The ground connections at the motherboard will oxidize, increase in resistance, and burn causing internment or no connection. Just curious if you need a supply because one is missing or if having functional issues with the machine (which might actually be the harness). Unlike the S2000 for which I stock about 100 supplies since they go out frequently, I do not stock a single spare supply for the S+ since have never needed one and don't expect to need one. Hope this continues to hold true as I still have a few (about 50) old S+ machines in stock that I need to refurbish some day.