First thing you need to know about the PSU is that its proprietary for all the HP MSS and Datavault Servers so what you have on hand will not work and would require you to change the wiring. Since all the PSU's in these servers are compatable and use the same pin outs you can review the information in the links below to help guide you.
PSU info in the Sites WIKI:
http://www.mediasmartserver.net/wiki/in ... wer_SupplyWhere to purchase a replacement PSU:
http://www.mediasmartserver.net/2010/07 ... rt-server/Guide on how to replace the PSU:
http://www.mediasmartserver.net/2009/08 ... er-supply/While you can check the Power output from the PSU to see if the PSU is outputing power the thing is that when a load is placed on a PSU it could fail to function properly. Before I would look at the PSU I would rule out my System and Storage Pool drives because it only takes 1 bad drive to keep WHS from booting properly.
At this point in time your issue may not be the PSU but with an issue with either your System Drive or one of your Storage Pool Drives. If you were to back out or disconnect all your storage pool drives and any externally connected devices eSTATA and USB, leaving only the System Drive connected then try to boot the server. If the server boots you will get lots of messages about missing drives and corrupt client backup databases. This is to be expected since the storage pool drives are not in the server. If the server does not boot up and you see the same results then shut it down and remove the System Drive and connect it to another computer and run CHKDSK /r on the drive. Your system drive has 2 partitions on it named SYS and DATA. Run CHKDSK /r on both partitions. This will attempt to repair any issues your having with the system drive. After that then reconnect Only the system drive and see if the server boots up. If it does then shut it down and reconnect your storage pool drives.
If you like you could also connect the storage pool drives and run CHKDSK /r on those as well to make certain they are in good working order. Running CHKDSK /r will take a great deal of time its not 5 min ordeal but can take in some cases hours to complete. All your Storage Pool Drives are named DATA. Now if you look at them it will appear that there are no files on them but they are in a hidden folder named DE so if you set your computer to view Hidden Files and Folders you will then see the folder DE and in there you will be able to see the storage pool data that is stored on that particular drive. Its important to mention while you can copy data from a storage pool drive its very important not to modify in anyway the data thats on the storage pool drive or you will risk corrupting your storage pool.
If your able to resolve your issue and get your server to boot then I would recommend you download and install Home Server Smart from the link below. This will help you monitor the health of your hard drives.
http://www.dojonorthsoftware.net/Freebi ... SMART.aspxIf your Client Backup Data base is important then I recommend you install BDBB and if you want to be informed if there there are issues with your server then I recommend Remote Notification both are available for download from this sites ADD-INS TAB.
The last thing I can mention is if you want to know if your server is functional you could take a single hard drive 80GB or larger and attempt to perform a Server Recovery but with only 1 drive perform the Factory Recovery. To place an additional load on the PSU you could then plug in everything you had connected to the server but DO NOT add your drives to the storage pool or they will be formatted just leave them as unmanaged drives. If everything looks good then you can disconnect the drives and other connected devices and then shut the server down and proceed with running CHKDSK /r on your drives as mentioned earlier.
Good Luck and please let me know how things progress with getting your server functional again.