Does your prtdiag -v shows any statuses of power supply? If yes, then my following advise will not follow.
If NO, then I suspect it could be an intermitent PSU failure, not necessarily it wil show up in the messages file, but I have "seen" it as a "silent killer" usually with no clues at all.. From experience I guess it could be ok after PSU replacement, but if you think I might be wrong, then Im sorry.