[Elecraft] Sudden K3 shutdown

[Jay Caldis]

Out of no where, my K3 when I key the keyer, P or memory, will just shut down (no power).  I power it up and it goes right back to were I was as if nothing has happened.
This will happen every now and then. Like yesterday during the CW Contest, it shut down 4 times in three hours.

Does anyone out there know what the problem may be? SWR is 1/1 running 100 watts and ATU is used.  

I do not want to send it back if it is something I did. Any help would be appreciated.

Jay KT6Y