Hello, I've noticed a problem in the past 8 months some of our APS-SL's. I've replaced 4 in different locations on our network. (We have about 70 SL sites approx.- never bothered counting them) I've asked locally but I've been told that there is no particular problem with the SL power supply. Some failed after powering off and on the system but others have just failed by themselves. Most of these systems are 6 yrs old now and have been trouble free since installation. We've been told that the IPX 500 is the replacement but SL spares will be available if required. Just wondering if anyone has had similar problems with this piece of kit. I'm trying to plan spare requirements for the SL for the future for my department as I expect these systems will be in service for some years to come. Thanks for your time.