Yesterday I repaired two fans for fitting into my rig. I just fitted them all back for a more efficient configuration but I thumped the outer case a few times to get it to fit back together. Now when I turn on the computer it sounds like the power supply is tripping on me. It starts up for 2-3 seconds then dies and repeats. Have I trashed the PSU ? It's an old Antec earthwatts , model ea-650w