I've contacted Microsemi for the PRS-45A user guide, but they are not helpful. Only when you buy stuff from them or from channel partners they are willing to help. So there is only the internet and the timenuts list as starters. As mentioned in the other thread, the user guide for the PRS can be found on a manuals site. Also check the CsIII 4310B user guide as it has more details. And try the monitor software, it will show the condition. There is also more info in the thread in the metrology section on these Datums. I made some posts on mine there, but at the moment i don't have much time (work

)
Would be interesting to see the insides of the PRS-50, wonder how much they match with the PRS-45. Powersupply for the 50 can be -36V to -62, 2A is plenty. Maybe you have something suitable.
The maser is something else. You can adjust the PRS if you get both working...
One of my PRS boxes has a big dent on the bottom. Must have been dropped or so. But no rattle and it just works. I did have a look inside before powering it up. Found bugs inside, but those were of the dead kind.
By the way, this thread should really be in the metrology section.... Probably would have been the first maser in there.