phadobas Well, that was a detailed report about that ticking, which always tick in the technical staff head, I guess!!!
You said you reset the PW card. Since you have a dual power blocks,how about taking it out of service and observe the situation for a while, if the tick disappears, then the fault is known in the removed PW, If NOT put it back in place and remove the other PW...and then observe for a while...and one more thing "it is not true to exlclude any installed card to be a cause of a certain tech problem..so check your other cards in that PIM"
Hope that could shed some light of help...
Good Luck